The Twitter situation was a bit different: I built the very first Android Twitter client which grew to millions of users. We later got acquired by TweetUp and I'm partly responsible for their strategy to acquire other popular clients, too. We basically owned 60%+ of the third-party market within months with the potential of 'migrating' a large portion to a new tbd Twitter competitor. Needless to say Twitter wasn't happy, and the rest is history. Never build on somebody else's turf.