[Loopy]

I'm with Facebook on this one, users to some degree trust that their Facebook information isn't freely available on the web. Thats an integral part of their business model that the communication is only with friends. As most people find communication with friends to be more important than communication with others on the web i believe that facebooks business model is far superior to twitters and so there is no reason to change it.

[peter123]

As far as business models are concerned, having data that is open is more likely to lead to better web monetization like contextual ads. The ability to have inbound links from referral sites and Google is important for ads.