The point is the triviality of a Twitter clone and the lack of any significant unique contribution that is difficult to copy. Right now, ALL they have is their

The point is the triviality of a Twitter clone and the lack of any significant unique contribution that is difficult to copy. Right now, ALL they have is their marketshare. Google has competitors, but they can't just upset Google overnight because it is really hard and takes a really long time to build a search facility of equivalent utility to the one Google provides. While some people challenge them, Google is still the objective king in searches, and companies with a huge amount of resources, like Microsoft, struggle to supplant Google in the quality of their offering. Facebook is a very complex system with a lot of support for a lot of different things. Facebook is more in line with Twitter in that it's strongly dependent on network effects, but Facebook requires investment of significant time in building relationships and composing a profile; they have some reasonable sense of lock-in here. And if you've looked around, it is still difficult to develop a platform that does everything Facebook does (or more), especially with Facebook's rapid deployment of analogous features anytime a competitor tries to one-up them. They copied and thereby neutered the viability of Circles lickety-split and Google+ could no longer claim a significant feature advantage for those concerned about privacy. Twitter is just a stream of short strings, easily scrapeable and convertible. The site can be cloned on a conceptual level in a couple of days. Twitter may have done some serious scaling work, but in the end they have no unique offering, no killer feature, nothing that a normal developer would have difficulty or serious effort duplicating at the conceptual level. Scalability of course takes time, but it's highly implementation dependent and occurs as necessary; Twitter's internal performance is not a serious user-facing barrier or feature. In fact, Facebook and Google+ already include all the functionality of Twitter. There is no reason to stay on Twitter other than pure network effects.