This subproject looks at Spotify’s relation to advertising. Its contribution consists in devising industry mapping, analytical categories, and quasi-ethnographic observation of various actors. The general question raised is: How do digital markets actually work? Who are the most important actors, and what is the role of advertising in driving and in making these markets? More specifically, a premise of this research is that digital markets include a considerable part of speculative activity. Using Spotify as a case, the project looks at three facets of speculation related to advertising. Based on a mapping of Spotify-related intermediaries and services, it studies – first – programmatic advertising, with a specific focus on ad exchanges/real-time bidding (RTB). Second, it looks at venture capital speculation, especially where such speculation is based on advertising-related promises (e.g. Spotify providing psychographic raw data). Third, and finally, this research studies the underground or informal economy of market places that offer illicit search optimization (ad fraud, bots), such as Black Hat Market. Overall, the sub-project is meant to develop the term arbitrage into an analytical category for understanding digital markets, and today’s music and video aggregation politics in particular.