Since the library does not require any server-side code on your server, you can now create a Facebook application that can be hosted and ran on any web site.
Almost all Facebook APIs are supported except for Photo Upload Profile Set FBML.
It pretty much opens up for building applications that run on the Facebook platform and you can extend them off to any web site.
Curious to see how this would flow, but you could basically put a version of Facebook anywhere you like such as Google Home Page and any other home page environment.
