Unlike the other two, Google used to be good about avoiding walled gardens and simply monetizing services provided on open platforms. Buzz was federated. Gchat was federated. Android lets you run what you want. Chrome never stagnates and actively builds new features to make the web more useful. Then Google+ (instead of Buzz on pubsubhubbub), Hangouts Chat (instead of XMPP) and now Google Chat (instead of Matrix) came along with the Facebook and Apple style walled garbage dump lock-in.