...tear down that wall.

You have to love the timing of the Open Social API announcement. Facebook is not worth $15B or $3 for every person on earth...

As pmarca puts it:

This is the exact same concept as the Facebook platform, with two huge differences:

• With the Facebook platform, only Facebook itself can be a "container" -- "apps" can only run within Facebook itself. In contrast, with Open Social, any social network can be an Open Social container and allow Open Social apps to run within it.
• With the Facebook platform, app developers build to Facebook-proprietary languages and APIs such as FBML (Facebook Markup Language) and FQL (Facebook Query Language) -- those languages and APIs don't work anywhere other than Facebook -- and then the apps can only run within Facebook. In contrast, with Open Social, app developers can build to standard HTML and Javascript, and their apps can then run in any Open Social container.

In keeping with my thoughts on 3D virtual worlds, the walled garden approach is not the end state, the "internet of virtual worlds" is. I think we're going to see this with Facebook, MySpace and others eventually becoming part of an "internet social spaces" connections between bits and pieces of ourselves, photos on flickr, blog on blogger, twits on twitter, profile on myspace, maps on geocommons, restaurant reviews on yelp, plus whatever we think of next week. Tying all of this together is going to be remarkably cool.

Technology like OpenID is really useful, and that's why you see Enterprise players like Oracle on the agreement. Now Facebook has a great UI and momentum, so there is still a really huge chance that this effort will fail if it turns out that no one uses it effectively, but I think there will be at least one innovation out there that will cause Facebook to pull down the wall towards interop of their data...