Digital marketing adoption of microenterprises in a technology acceptance approach

. External knowledge sources such as professional social media accounts represent an understudied domain in the digital media adoption literature of small enterprises. This article extends the Technology Acceptance Model with two additional factors – external knowledge source and trust in digital marketing professionals – to better understand the digital marketing adoption of microenterprises. We collected and analyzed data from 181 microenterprises using online survey and structural equation modeling methodology. Results indicate that participation in events and following professional Facebook groups are positively related to perceived ease of use, while following professional Facebook groups, blogs, and vlogs, and meeting consultants are positively related to perceived usefulness. Besides, trust in marketing professionals has a significant effect on both perceived ease of use and perceived usefulness. By applying the technology-in-practice literature to digital marketing adoption, the article highlights that marketing professionals can be a bridge between academia and small business managers by contextualizing and translating formal knowledge to practical easy-to-understand knowledge.


Introduction
Digital marketing provides numerous advantages for small businesses (Eze et al., 2021;Urbinati et al., 2020).Yet, a lot of small businesses do not have a digital marketing strategy, their adoption of digital marketing is slow, or their utilization is ineffective (Bollweg et al., 2020).Small businesses struggling with digital marketing adoption perform worse than their competitors who have a digital marketing strategy (Taiminen and Karjaluoto, 2015).
Previous studies have identified several reasons that explain slow digital marketing adoption among small businesses (Murphy and Kielgast, 2008) and limited financial resources to outsource (Ren et al., 2010;Ritz et al., 2019, p. 181).Small business ownermanagers also play a major role in the process: their knowledge, expertise, and understanding of digital marketing affect digital marketing adoption (McGowan and Durkin, 2002;Ritz et al., 2019;Wolf and McQuitty, 2013).When the enterprise lacks internal knowledge sources, the owner-manager is forced to leverage external knowledge sources to learn about digital marketing.
Previous research examined the impact of different knowledge sources on organizational innovation and decision-making (Simao and Franco, 2018).Such research found that collaborative platforms and knowledge sharing among peers play an important role in small and medium enterprises' (SMEs') digital market knowledge acquisition and digital transformation (Alford and Jones, 2020;Crupi et al., 2020).However, to the best of our knowledge, no studies have investigated the effect of different external knowledge sources on digital marketing adoption in a microenterprise context.In addition, the abundance of sources and uncertainty raise the question of whether the owner-managers of microenterprises trust marketing professionals.
In this article, we extend the Technology Acceptance Model (TAM) with two factorsexternal knowledge sources and trust in digital marketing professionals -to explain the digital marketing adoption of microenterprises.We explore external knowledge sources that microenterprise owner-managers use to acquire knowledge about digital marketing and their effect on the adoption of digital marketing using the TAM framework.We also investigate the effect of perceived trust in marketing professionals who provide Mode 2 knowledge -knowledge produced in the context of application meant to solve a specific problem-of digital marketing on the digital marketing adoption of microenterprises.

Microenterprises and the digital marketing adoption
Digital marketing can be defined as a management activity with the goal of identifying, preparing for, and satisfying the needs of customers (or other stakeholders) profitably in the digital environment (Kannan and Li, 2017;Rowley, 2008).A company's digital marketing strategy determines the number and intensity of tactical level uses of digital marketing tools.However, small businesses often focus on the actual use of digital marketing channels without any strategic thinking (Nikunen et al., 2017).Digital marketing for them is mostly implemented in an ad hoc manner where goals and measures for the channels are not specified; digital marketing strategy consists of the allocation of limited resources among different digital media channels (Taiminen and Karjaluoto, 2015).Consequently, SME digital marketing adoption should encompass both the use of digital marketing tools and the existence and execution of a digital marketing strategy.
Microenterprises, defined by the European Union as companies with fewer than 10 employees and an annual turnover or balance sheet below €2 million (EU 2003), are characterized by the main peculiarities of SMEs, such as a lack of resources and expertise in marketing (Reijonen, 2010), but to a greater extent (Zhou et al., 2012).Microenterprise owner-managers are usually the creators of most of the organization's strategic and tactical (digital) marketing activities (Fu, 2011;Gamble et al., 2011;Kottika et al., 2013;Leppard and McDonald, 1991;Sadler-Smith et al., 2003).For instance, in the early stage of the company, microenterprise marketing is inherently intuitive and based on the knowledge and experience of the owner-manager (Gilmore and Carson, 2018).Previous studies also confirm that the use of digital marketing tools depends on the owner-manager's supporting attitude towards marketing (Akunuri, 2011;Alford and Page, 2015).
Despite its benefits, most small businesses struggle with digital marketing adoption (Bollweg et al., 2020;Garzoni et al., 2020;Eze et al., 2021;Pollák and Markovič, 2021;Ratnasingam et al., 2021).Strategic decisions about digital transformation do not automatically improve performance, because it requires small businesses to rethink and change their business model (Bouwman et al., 2019).For instance, a representative survey that measures the digitalization of SMEs in Hungary found that 41 % opted for an online promotional campaign; however, 32 % use only one digital channel (Digiméter, 2021).Furthermore, 26 % use an online tool to acquire new customers, but only 11 % have a customer relationship management (CRM) module (Digiméter, 2021).
Small enterprises are often left alone to figure out how to adopt digital marketing (Ritz et al., 2019).Several barriers to digital marketing adoption relate to the owner-manager.For instance, entrepreneurs often lack digital marketing competency and knowledge (Taiminen and Karjaluoto, 2015).They are not aware of the benefits of digital marketing (Harrigan et al., 2011;Wolcott et al., 2008) or they struggle to understand the benefits and how digital marketing will contribute to the profitability of the business (Alford and Jones, 2020).Entrepreneurs also lack the analytical skills to generate insights from digital data and to measure the impact of their digital marketing investment (Alford and Jones, 2020;Ateljevic, 2007;Kotler and Keller, 2016).

The Technology Acceptance Model
To understand the use of digital marketing tools and the application of a digital marketing strategy, we initiate our theoretical framework from a technological approach.A multitude of technology acceptance models exist in the literature (Compeau et al., 1999;Davis, 1986;Davis et al., 1989;Moore and Benbasat, 1991;Thompson et al., 1991;Venkatesh and Davis, 2000;Venkatesh et al., 2003).Each model has the same dependent variable, usage, but uses various antecedents to understand acceptance of technology.According to Ahearne et al. (2004), an implicit assumption in all these models is a positive and linear relationship between performance and usage.Another underlying assumption is that technology utilization is a proxy of its perceived effectiveness.
In the context of the present article, we opted for the Technology Acceptance Model (TAM) by Davis et al. (1989).The probability of system use (in this case, digital marketing adoption) is analyzed through the mediating role of perceived ease of use (PEU) and perceived usefulness (PU) in their relation to systems characteristics (external variables) (Oye et al., 2014).External variables have direct effect on PEU and PU.Most studies about TAM, among them Davis (1989), presume that perceived ease of use is directly linked to perceived usefulness.The utilitarian value of using a certain system is influenced by its effortless use, for example by requiring the least amount of work possible by an individual who starts using this particular system.Rauniar et al. (2014) analyzed digital marketing tool (Facebook) usage in a model where perceived ease of use influenced actual usage through perceived usefulness.Furthermore, intentions to use technology determine whether a person will use the technology.
The TAM we use focuses on how perceived ease of use and perceived usefulness affect digital marketing adoption.Based on the literature, we developed the following hypotheses: H1: The perceived ease of use of digital marketing positively affects the perceived usefulness of digital marketing in the case of microenterprises.H2: The perceived ease of use of digital marketing positively affects digital marketing adoption (digital marketing usage and the existence/elaboration of digital marketing strategy) in the case of microenterprises.H3: The perceived usefulness of digital marketing positively affects digital marketing adoption (digital marketing usage and the existence of digital marketing strategy) in the case of microenterprises.
Trust in digital marketing professionals A SME, and especially, a microenterprise, heavily relies on external sources, because it does not have the required range of knowledge and skills to implement a digital marketing strategy (Kautonen et al., 2010).Previous studies have revealed that trust may play an important role in a SME's business decisions related to external sources of knowledge (Welter and Kautonen, 2005).When trust in the advisor is strong, then the SME ownermanager is more likely to believe that the applied (e.g., digital marketing) tool results in better performance, and is more convenient and transparent for the firm to use.Furthermore, if the owner-manager trusts one marketing professional, this positive perception might transfer to another, as yet unknown, marketing professional (Hu et al., 2019;Stewart, 2003).Previous research concluded that trust is an important determinant of PU, because if the experts cannot be trusted in accordance with the individual's beliefs, then the individual has no reason to expect any actual benefit from using the system (Pavlou, 2003).
Based on this, we developed the following hypotheses: H4: The perceived trust in digital marketing professionals positively affects the perceived ease of use of digital marketing in the case of microenterprises.H5: The perceived trust in digital marketing professionals positively affects the perceived usefulness of digital marketing in the case of microenterprises.

Digital marketing knowledge acquisition
Knowledge sources can be incorporated as direct antecedents of behavioral beliefs that affect attitudes (Sparks and Pan, 2009).Gibbons et al. (1995) differentiate two ways of knowledge production.The first is called Mode 1; it encompasses 'traditional' knowledge production and is considered sound scientific practice.In contrast, Mode 2 is characterized by knowledge production in the context of application; it is socially accountable and reflexive and includes a heterogenous set of practitioners.Mode 2 is problem solving that is organized around a particular application.Knowledge is intended to be useful to someone.Supply and demand factors operate in Mode 2. While Mode 1 refers to the knowledge generated by universities and researchers, Mode 2 refers to the knowledge generated by practitioners and consultants.
There are failures in the direct transfer of Mode 1 knowledge from academia to businesses (Ruhanen, 2018).For instance, small businesses do not always understand the relevance of formal knowledge (Danis and Shipilov, 2012).The theory of technology-inpractice posits that technologies are intertwined and shaped by the user, and they must be seen in the context of practice (Morgan-Thomas, 2016).Indeed, most owner-managers do not engage in formal learning; instead, they opt for experiential learning, i.e., learning by doing, along with the utilization of Mode 2 knowledge sources.Some information (knowledge, know-how) is freely available on the internet in the form of white papers, blogs, vlogs, or free professional brochures.Numerous practitioners and consultants provide digital marketing consultancy, services, and related knowledge to SMEs (Danis and Shipilov, 2012).
Consequently, we formulated the following research questions: RQ1: Among the Mode 2 knowledge sources that owner-managers of microenterprises use to get information about digital marketing, which sources affect the perception of perceived ease of use of digital marketing?RQ2: Among the Mode 2 knowledge sources that owner-managers of microenterprises use to get information about digital marketing, which sources affect the perception of perceived usefulness of digital marketing?
Figure 1 summarizes and integrates our hypotheses and research questions in our research model.

Sampling and data collection
To test our hypotheses and answer our research questions, we conducted an online survey.With this study, we specifically targeted microenterprises.We distributed the link on several online platforms where SME owner-managers are typically present.We collected data with the help of university students who received credit for their recruitment work and determined the sample size following the ten times rule (Hair et al., 2014).A convenience sample of 181 respondents was collected.
All 181 respondents were owner-managers of a microenterprise.Almost half of the enterprises (49.2 %) had less than HUF 10 million (cc.€27,700) as yearly revenue, while 35.9 % had between HUF 10 and 60 million (cc.€166,700).The rest (14.9 %) had more than HUF 60 million in yearly revenue.Among the respondents, 30.4% indicated that they do not spend on marketing communications while 26 % spend less than 1 % of their yearly revenue.Another 30.4 % spend between 1 % and 5 % of their yearly revenue on marketing communications, while only 13.3 % spend more than 5 %.Regarding the main activity of the enterprises, the majority (82.3 %) are operating in the service sector, while only 12.7 % are in the manufacturing sector; 5 % indicated other main activities.Among the enterprises in the service sector, 12.7 % are engaged in trading activities, and respectively 8.3% belonged to the construction sector and to the hospitality sector.Related to the different digital marketing tool use, on a five-point scale ('1: we did not use it at all' to '5: we used it intensively'), the most frequently used was Facebook (M=3.21,SD=1.57), followed by company website (M=3.11,SD=1.73), then Instagram (M=2.29,SD=1.56), search engine optimization (SEO) (M=2.15,SD=1.43),Google Ads/AdWords (search engine advertising) (M=2.09,SD=1.41),YouTube (M=1.88,SD=1.33), electronic direct mail (M=1.82,SD=1.26), company-generated blogs (M=1.78,SD=1.32), and finally, classic or interactive banners (M=1.53,SD=1.05).

Measures
To assess perceived ease of use (5 items) and perceived usefulness (8 items), we adapted items from Davis (1989) and Ritz et al. (2019).We assessed trust in digital marketing professionals using five items adapted from Moorman et al. (1993) and Cheung and Lee (2001).Regarding these items, answers were given on a five-point Likert response scale (1: completely disagree, 5: completely agree).The questionnaires were adapted following the Beaton-Bombardier method (Beaton et al., 2000).Table 1 summarizes the list of measures used in our questionnaire.

Measures
Trust in digital marketing professionals (source: Cheung and Lee, 2001;Moorman et al., 1993) I believe we can trust digital marketing professionals.
Digital marketing professionals act sincerely in dealing with customers.I find that the methods, analyses, and predictions used by digital marketing professionals are reliable.
Digital marketing professionals have sufficient expertise and resources to help entrepreneurs in marketing-related issues.
Digital marketing professionals are honest with their consumers.
Perceived ease of use (source: Davis, 1989;Ritz et al., 2019) Learning things related to digital marketing would be easy for me.
I would find it easy to achieve objectives related to digital marketing.
My interaction with digital marketing channels would be clear and understandable.
It would be easy for me to become skilful at handling digital marketing channels.I find developing digital marketing easy.
Perceived usefulness (source: Davis, 1989;Ritz et al., 2019) Using digital marketing would enable the company to accomplish growth more quickly.
Using digital marketing would improve business performance.
Using digital marketing would increase our productivity.

Measures
Using digital marketing would enhance the company's effectiveness to increase awareness of the business.
Using digital marketing would enhance the company's effectiveness to increase customer engagement in the business.
Using digital marketing would enhance the company's effectiveness to increase lead generation for the business.
Using digital marketing would make it easier to run the business.
I believe digital marketing would be useful for the business.
Source: Authors' own research.
We assessed the knowledge sources that owner-managers use to learn about digital marketing by asking the following question: 'Please indicate how you got information about digital marketing in the last 12 months.'We provided the following possible answers: 'conference', 'workshop ', 'professional books, brochures', 'blogs and vlogs', 'professional portals', 'professional Facebook groups', 'consultants', 'agencies', 'other (open-ended question)', 'none of the above'.Respondents could indicate multiple sources.Each knowledge source received a binary code (0: no use; 1: use).
Our scale assessing digital marketing strategy is based on Ryan (2014) and Kotler and Keller (2016), combining their views on the elements of marketing strategy.We asked the respondents the following question: 'Please indicate which of the following processes/ elements are present in your enterprise.' Answers were given on a three-point scale '1: it is not part of company practice', '2: present verbally' and '3: present in written form'.Respondents had to evaluate the following elements of their digital marketing strategy: mission statement, competition analysis, market segmentation, target group specification, positioning, digital marketing plan with concrete goals, digital tools assigned to each goal, responsibility assigned to each goal, and measurement of results.We added scores to create a single summed variable.
We measured digital marketing tool use by an adapted and modified version of the general classification of Taiminen and Karjaluoto (2015).We asked the respondents the following question: 'Please estimate with what intensity you have used the following digital marketing tools last year.'Answers were given on five-point scale from '1: we did not use it at all' to '5: we used it intensively'.Respondents had to assess the intensity of use concerning the following tools: Google Ads/AdWords (search engine advertising), search engine optimization, Facebook, Instagram, YouTube, other social media, company website, company-generated blogs, electronic direct mail, and classic or interactive banners.Again, we summed the scores to create a single variable.
At the beginning of the questionnaire, we asked three control questions to make sure only owner-managers of microenterprises participated in the survey.The first concerned the role of the respondent ('What is your role in the enterprise?').Respondents could only move on when they chose 'owner' or 'CEO'.The second control question concerned the number of employees ('How many employees work at the enterprise?').Respondents could only move on when they chose the option 'between 0 and 9 people'.The last question concerned the yearly revenue of the enterprise ('What was the yearly revenue of the enterprise in the previous fiscal year?').Respondents had to indicate that their yearly revenue was less than.€ 2 million to be able to continue the questionnaire.
Finally, we asked two descriptive questions at the beginning of the questionnaire.One concerned the marketing communications spending of the enterprise ('Please estimate the % of your yearly revenue that you have spent on marketing communications during the previous fiscal year.')and the other was regarding the main activity of the enterprise ('What is the main activity of the enterprise that you represent?').

Data analysis
We used Partial Least Square Structural Equation Modelling (PLS-SEM) that is more appropriate for exploratory research and requires fewer assumptions than covariance-based structural equation models.Furthermore, PLS-SEM is more adapted to smaller sample sizes and complex models as well (Hair et al., 2017).PLS-SEM is also ideal for theory extension (Hair et al., 2011).We analyzed data using SmartPLS 3.0 (Ringle et al., 2015), handling missing data with pairwise deletion.For the PLS model, we used a path weighting scheme: the maximum number of iterations was 300, the abort criterion was reached after 7 iterations (Hair et al., 2021).To calculate the confidence intervals of the path coefficients, we applied a bias-corrected and accelerated (BCa) bootstrap method with 500 samples at a 0.05 significance level.

Knowledge sources
Table 2 summarizes the frequency of use regarding each knowledge source.As less than 10 % indicated that they used agencies or attended workshops, we decided to merge these categories with other sources.Thus, we created two new categories: 'events' by merging conferences with workshops (22.1 % of the respondents indicated attending either conferences or workshops to be informed about digital marketing), and 'consultants' by merging consultants and agencies (18.2 % of the respondents indicated that they talked to either consultants or agencies to be informed about digital marketing).Consequently, in the PLS-SEM model, we included six sources: professional Facebook groups, blogs and vlogs, professional portals, events, professional books, and consultants.

Assessment of the measurement model
We tested the quality of our measurement model including four variables: trust in marketing professionals, perceived usefulness, perceived ease of use, and digital marketing adoption.First, we verified the reliability of the constructs using two unidimensional indicators: Cronbach alpha and Dillon-Goldstein`s rho.Then we checked the construct validity, that is to what extent latent variables explained variations in the indicators using composite reliability (CR) and the average variance extracted (AVE).Table 3 contains the reliability and construct validity measures for each latent variable.All our variables have a good reliability: both the Cronbach's alphas and the Dillon-Goldstein's rhos are higher than 0.7 (Hanafiah et al., 2020).Furthermore, the average variance extracted was higher than 0.5 indicating acceptable construct validity for each latent variable (Fornell and Larcker, 1981).Finally, we checked the discriminant validity of the constructs using the Fornell-Larcker criterion.We compared average variances extracted with the squared correlations of each construct with other constructs.The criterion for discriminant validity is that the average variance extracted should be larger than the highest correlation with any other constructs (Fornell and Larcker, 1981).Table 4 summarizes the data.The data indicates that all latent variables have acceptable discriminant validity as well.

Assessment of the Structural Model
Regarding the variances explained by the model (R 2 values), 30.9 % of the variances in digital marketing adoption are explained by the model, while 30.2 % of variances are explained in the case of perceived usefulness and 25.2 % is explained in the case of perceived ease of use.
Due to the exploratory nature of our research, we did not examine goodness-of-fit statistics (Riou et al., 2016;Henseler, 2018).Table 5 summarises the path coefficients and the bias corrected bootstrapped confidence intervals of the PLS model.Results indicate that perceived ease of use does not affect the perceived usefulness of digital marketing.Thus, H1 is not supported.
Both perceived ease of use and perceived usefulness positively affected digital marketing adoption.Consequently, H2 and H3 are supported.Furthermore, perceived usefulness had a stronger effect on digital marketing adoption than perceived ease of use.
The trust in digital marketing professionals positively affected both the perceived ease of use and perceived usefulness of digital marketing.Respondents who have more trust in marketing professionals are more likely to have higher perceived ease of use and higher PU.Thus, H4 and H5 are supported.
Regarding the knowledge source, results indicate that attending professional events (conferences and workshops) positively affected the perceived ease of use of digital marketing.Furthermore, the use of professional Facebook groups also had a trending positive effect on the perceived ease of use of digital marketing.Perceived usefulness is positively affected by blogs and vlogs and professional Facebook groups with consultants also having a trending positive effect.

Discussion
Despite its proven benefits, small businesses, especially microenterprises are lagging larger companies when it comes to digital marketing adoption.We extended the Technology Acceptance Model of digital marketing by including two antecedents: the perceived trust in marketing professionals and the external knowledge sources of digital marketing.
Our first three hypotheses concerned the core Technology Acceptance Model.Regarding our first hypothesis, our results reveal that the perceived ease of use of digital marketing does not affect perceived usefulness.Thus, our first hypothesis is not supported.Our results are similar to the results of a previous study that found a negative relationship between ease of use and usefulness regarding social media adoption (Siamagka et al., 2015).The authors explained their results with the complexity of social media usage: social media seems to be easy to use at the beginning; however, at an advanced level, it is more difficult to use, but it also provides more benefit to the enterprise.Consequently, perceived usefulness is dissociated with perceived ease of use as small businesses learn to leverage social media more efficiently.
Regarding H2 and H3, our results indicate that both the perceived ease of use and perceived usefulness of digital marketing affect digital marketing adoption.Furthermore, our analysis reveals a stronger effect for perceived usefulness.Consequently, H2 and H3 are supported.Our results are in line with previous research that also found that both perceived ease of use and perceived usefulness play a major role in digital marketing adoption (Chatterjee and Kumar, 2020;Ritz et al., 2019).The fact that perceived usefulness has a stronger effect on digital marketing adoption can be explained by previous findings about how not recognizing the benefits of digital marketing creates an important barrier of adoption in the case of small businesses (Alford and Jones, 2020;Harrigan et al., 2011;Wolcott et al., 2008).
Regarding H4 and H5, our analysis reveals that trust in marketing professionals positively affects both the perceived ease of use and the perceived usefulness of digital marketing.This result is in line with the result of previous empirical studies that found that trust in professionals results in better perceived performance (Pavlou, 2003;Welter and Kautonen, 2005).Furthermore, previous studies found similar relationships among trust and specific elements of TAM, especially perceived ease of use and perceived usefulness (Wu et al., 2011).Small business owner-managers tend to work better with professionals they trust (Gefen and Straub, 2003).Based on a good relationship with the marketing consultant, these firms perceive the given tools as easier to use, and their benefits more transparent.
Finally, regarding the Mode 2 knowledge sources of digital marketing, our analysis reveals that the perceived ease of use of digital marketing is positively affected by attendance at events and the use of professional Facebook groups (marginal effect) as knowledge sources.Furthermore, perceived usefulness is positively affected using professional Facebook groups, blogs, and vlogs, and discussions with consultants (marginal effect).
Our results on the influential role of professional Facebook groups as knowledge sources confirm previous findings about the importance of experience sharing among peer groups and the desire to learn from the example of others who have the same concerns and problems (Alford and Jones, 2020).Although professional Facebook groups are managed by marketing professionals (consultants or digital marketing companies), they also enable peer-to-peer conversations especially in the comment sections of the posts.Blogs and vlogs also enable two-way communication where the owner-manager can ask questions or read others' comments as well.
Social influence and perceived norms also explain our results about professional Facebook groups.For instance, based on what they experience in a Facebook group, the more an owner-manager believes that others use a digital marketing tool, the more they will believe that the tool is easy to adopt (PEU) or that the tool will benefit the company (PU).The direct and indirect effects of social influence and perceived norms are well documented regarding new technology acceptance (Schepers and Wetzels, 2007).
In line with the technology-in-practice literature applied to the digital marketing adoption (Morgan-Thomas, 2016), our results also prove the importance of context.In the professional Facebook groups and at professional events (conferences and workshops) participants meet practical examples and digital marketing solutions tailored to the needs of a microenterprise.Marketing professionals who specialize in small business marketing can also been seen as a bridge between the formal Mode 1 knowledge and small business ownermanagers as they contextualize Mode 1 knowledge and translate it to an easy-to-understand practical and useful knowledge.

Theoretical contribution
Our theoretical contribution concerns the application of the Technology Acceptance Model to the digital marketing adoption of microenterprises and the external knowledge acquisition of small businesses.First, we provide empirical evidence that the perceived ease of use and the perceived usefulness are unrelated when the model concerns digital marketing adoption.We extended previous results regarding social media adoption to digital media adoption (Siamagka et al., 2015).The unrelatedness of the perceived ease of use and perceived usefulness seems to apply to a wider digital marketing context; however, exploring the underlying mechanisms and the consequence of this phenomenon requires further examination.
Second, our results emphasize the importance of perceived usefulness over perceived ease of use regarding digital marketing tool usage and digital marketing strategy adoption (Alford and Jones, 2020).Besides, we applied an innovative measurement tool to assess digital marketing adoption.We assessed the number of digital marketing tools the enterprise uses and the elaboration of the enterprise's digital marketing strategy.This complex approach considers both the strategic and tactical level of digital marketing adoption and can contribute to a deeper understanding of small business digital marketing management.
Third, we integrated two antecedents -trust in marketing professionals and Mode 2 knowledge sources -in the Technology Acceptance Model regarding the external knowledge acquisition of small businesses.We provide empirical evidence that trust in marketing professionals is positively related to both perceived ease of use and perceived usefulness regarding digital marketing adoption.Thus, we extend previous findings about consultants to digital marketing professionals.Finally, we identified important Mode 2 knowledge sources such as professional Facebook groups, blogs and vlogs and professional events.The benefit of integrating external knowledge sources into the Technology Acceptance Model lies in associating knowledge sources with either the perceived ease of use or the perceived usefulness of digital marketing adoption.Consequently, we better understand how different knowledge sources contribute to the different aspects of the model.An essential finding of the study worth exploring is the dominance of social media knowledge sources in shaping small businesses' perception of the usefulness of digital marketing.

Practical implications
In addition to widening theoretical knowledge in the context of small businesses, our research contributes to company practice.According to our results, attendance at events and the use of professional Facebook groups contribute to the perceived ease of use of digital marketing.Thus, these two external knowledge sources might be recommended to microenterprises who lack knowledge regarding the use of digital marketing tools.
Additionally, it is also useful to note that microenterprises' perception of the usefulness of digital marketing is affected by blogs, vlogs, professional Facebook groups, and consultants.Consequently, these sources can be recommended to enterprises who have just started to get familiar with digital marketing but are not fully convinced that digital marketing adoption might be useful for their business.
Trust proved to be indispensable in the perception of how easy and how beneficial digital marketing could be for the company.This result implies that professional consultants should be trustworthy, reliable, and honest, and that they need to possess the required knowledge to be able to affect their clients' perception of the digital marketing tools they offer.Furthermore, organizations representing digital marketing professionals should work on ethical codes and regulations that ensure that less competent and less trustworthy marketing professionals cannot ruin the trustworthiness of the profession.
Finally, our results indicate that digital marketing adoption depends also on how beneficial owner-managers believe digital marketing can be for their company, and not only on how easy it is to apply.Highlighting the potential benefits of digital marketing in an easyto-understand and transparent way could gain even more importance in communication towards small businesses.

Limitations and directions for future research
This article has several limitations.The theoretical approach that intends to understand the different aspects of digital marketing adoption by microenterprises focuses on certain dimensions of knowledge acquisition and management.Connecting technology acceptance with trust is only one way to understand how small businesses use digital marketing in tactical and strategic perspectives.Another limitation is that the sample structure could have been more diverse in terms of market structure and industry sector, to be able to compare certain groups of companies' digital marketing adoption patterns.We gathered data in a specific country, which may limit the generalizability of our results.PLS-SEM methodology has certain limitations, too, although it can assess a wider range of situations, and it is proper for theory building (Hair et al., 2011).
Future research might expand the sample including various industries and markets.It might also validate the results on a more diverse SME sample, including larger enterprises as well.Regarding the digital marketing knowledge sources, further research might explore the role of Mode 1 knowledge in the digital marketing knowledge acquisition of small businesses.Given the importance of peer exchange, the role of bottom-up Facebook groups should also be investigated.
Regarding trust in marketing professionals, future research might explore the reasons for distrusting marketing professionals and how trust in marketing professionals can be reinforced.Trust in different types of marketing professionals could also be further explored.The question also arises whether trust in a given marketing professional could moderate the effect of their professional content on the digital marketing adoption of small businesses.

Conclusions
Digital marketing adoption provides several benefits and a competitive edge to small businesses.Despite the advantages, small businesses need help with digital marketing adoption.In this paper, we examined two factors, trust in digital marketing professionals and Mode 2 knowledge sources and their relation to the Technology Acceptance Model.Trust in digital marketing professionals has a significant positive relation to both the perceived ease of use and the perceived usefulness of digital marketing adoption.Moreover, social media knowledge sources such as professional Facebook groups and blogs and vlogs contribute to the perceived usefulness of digital media.Besides, attendance at professional events is related to the perceived ease of use.Future research should further explore how trust affects digital media professionals' effectiveness in a small business context and how social media knowledge sources can provide affordable and scalable solutions to help the digital media adoption of small businesses.

Figure 1 .
Figure 1.Research model 138 0.831 Notes: A = consultants, B = Blogs and vlogs, C = Professional books, D = Events, E = Digital marketing adoption, F = Professional Facebook groups, G = Perceived ease of use, H = Perceived usefulness, I = Professional portals, J = Trust in digital marketing professionals Source: Authors' own research.

Table 2 .
Source of information usage (%) Source: Authors' own research.

Table 3 .
Summary of reliability and construct validity of the latent variables Source: Authors' own research.

Table 4 .
Correlation among the constructs

Table 5 .
Correlation among the constructs Source: Authors' own research.