Doc Searls says in Let’s move tweeting off Twitter that most online communication isn’t owned by one company:
Blogging, emailing and messaging aren’t owned by anybody. Tweeting is owned by Twitter. That’s a problem.
It is one of the points I tried to make a few days ago. I don’t think we have to move away from Twitter. But I do think we need to at least make it possible for every company (and person) to have their own microblogging instance. And all these instances should be able work together.
The best solution is to make many thousands of interoperating services, just like email. This allows each company to host their own version. And all these services will work together. That way I can subscribe to your messages and you can subscribe to mine. If no subscriptions exist between two services, there are no messages transferred between them.