This article is preposterous. It claims the $5B Android annual revenue from $20 (GOOG ARPU from another article of $27.30) * 255 million activations. However the $27.30 number is simply Google revenues / google unique users per year. Thus that number is completely unrelated to Android revenues. My guess is that 95%+ of Android users are already Google customers and the marginal revenue they see from Android search ads is a small fraction of that.