Programmatic advertising rose in the early 2000s, aiming at streamlining the online media buying process. It offered marketers the means to buy millions of advertising impressions instantly and helped publishers increase their revenues. The deployment of automated algorithms for media trading led to a significant decrease in campaign setup and management costs and created a new revenue stream for online publishers. However, by the late 2010s, the emergence of ever more complex algorithms and the opaque practices of the Advertising Technology (AdTech) companies in charge of them have led to complaints that programmatic advertising functions largely as a “black box”. This article inquires into the programmatic media trading process, with a focus on the impact of the algorithms’ increased sophistication on the monetization strategies of online publishers. We analyze the case of, a leading Romanian newspaper, in its attempt to offset the decrease of revenue from printed circulation by increasing revenues generated through its online website. The findings show that publishers are forced to apply increasingly complex website monetization strategies. This can, in turn, lead to a loss of control over their advertising inventory and decreased bargaining power when facing AdTech companies, thus threatening the economic models of online publishing.