In July 2008 I wrote an article on my ekive.blogspot.com blog on the theme of "Twitter's Business Model Emerges?" In that post I covered the issue of Twitter's API throttling strategy. Back then I saw the possibility that the emerging ecosystem of apps like Tweetdeck and Seesmic could use platforms like Laconi.ca which became StatusNet to create a parallel twitter-like transport. The work that Dave Winer has been doing in advancing realtime RSS also offers an alternative federated twitter solution.
If Twitter keeps changing the rules on API access and plays favorites with their XMPP fire hose then the ecosystem could take matters in to their own hands and cut Twitter out of the loop. The sooner Twitter comes out with a viable business model where everyone can understand how Twitter has a viable future, the better for everyone. If Twitter keeps constructing walls to protect their position then there will be more incentive for players in the ecosystem to construct the parallel Twitter-verse where their future in no longer subject to the whim of Twitter.