@pyne @ipg
They did the same thing with RSS.

Google Reader was a top-tier RSS reader, which drained market share from both paid and free alternatives. But very soon after becoming the dominant RSS reader, Google abruptly closed it. Google told users to instead use Google+ (which is an entirely different thing). RSS suffered a massive blow.

Good new RSS readers have eventually returned, but there is no doubt that RSS suffered a massive setback from that. And I believe that was Google's ultimate intention: to cripple a competitive free alternative to their own business.