ad impressions are meaningless. eCPM in mobile ads has been on a precipitous decline. As an example, last year ad revenue made up ~15% of my total revenues and

ad impressions are meaningless. eCPM in mobile ads has been on a precipitous decline. As an example, last year ad revenue made up ~15% of my total revenues and my eCPM was around $3 (with paid apps and in app purchasing making up the rest). This year? It's barely a rounding error (< 1%) and my eCPMs are ~ $.10. Other developers are reporting the same thing across the board. Granted this is for iOS and not android, but I can't imagine android being a whole lot better. To make an analogy with the web, I think mobile ads are pretty much stuck in the Yahoo era. It only works because there are new suckers to replace the old ones. Almost all of the indie developers I know that have tried mobile advertising have said it doesn't give you a good ROI. I'm not sure what the solution is, but to me it's clear that the future for app monetization is paid apps and in app purchases. If you are going to rely on # of ad impressions to choose your platform you are looking at the wrong metric.