But making a copy is never enough. Users are only willing to migrate to a new platform for lower price, superior features, or when the original platform screws

But making a copy is never enough. Users are only willing to migrate to a new platform for lower price, superior features, or when the original platform screws up big time. Otherwise it's just more of the same, and now instead of sending a tweet, you now would have to use multiple platforms to reach the same audience which probably already uses Twitter anyway. If they really want people to move from Twitter like from Digg to Reddit or MySpace to Facebook they need a unique selling point. Having to use my real identity for a Twitter clone isn't one.