The Next Generation site is running a piece discussing new findings about in-game advertising. The results of collaboration between an ad firm and a research company show that ads in games are actually having an effect
on players. Double Fusion's involvement in the study throws the results into question. Take these statistics with a grain of salt: "75% of gamers engage with at least one ad per minute across most, but not all, game types; 81% of gamers engage at least every other minute. Less-cluttered ads are three times as effective at garnering gamer notice than ads that are either cluttered or within cluttered environments. While both contribute positively to ad engagement, placement of the ad in the primary camera plane (eye-level) is more important than large size ads. Not all ads are created equal - dynamic billboards, around-game interstitials, sponsorships, and interactive product placements all offer different levels of user engagement and pervasiveness in the game"
Eidos certainly thinks so; Kotaku notes that they've signed up with the same company
featured in this study.