Google is Android's customer. Before Android, the phone market was either screwed up locked down "smart" phones produced by the carriers or the iPhone which is

Google is Android's customer. Before Android, the phone market was either screwed up locked down "smart" phones produced by the carriers or the iPhone which is tightly controlled by Apple. Aggravating the iPhone option, AT&T has a lock on the iPhone, freezing out the other carriers. Without shaking things up, Google had little market for serving mobile ads. Nobody did Google-style searching -> web browsing on the screwed up "smartphones" and Google is at the mercy of Apple (to some extent) on the iPhone. With Android, Google is shaking things up and getting their opportunities (in spades) to serve ads to mobile browsers. The carriers saw iPhone as the major threat that it is, saw their smartphones losing popularity as people realized how poor their UI was, and still were paying lots of money for the smartphone software. AT&T has the iPhone locked up (for now), so Android is the only way for them to be competitive. Google did the "white knight" on the phone ecosystem: they offered the carriers software competitive with the iPhone and offered the phone manufacturers free software that didn't suck for development and didn't suck for UI. While neither is probably real happy with the leverage Google has over them and the disruption that Google is doing in their industry, the alternatives with Symbian or Windows Mobile is worse and more expensive to boot.