Microsoft's New offering and Facebook?
The new facebook API is pretty awesome, I have been using it for a few months now to integrate parts of a custom networking site into users exisiting facebook accounts.
Also Microsofts new PopFly thing is looking to be a contender to the likes of facebook, Facebook is too rigid to pull in all of the kids who want sparkly pink godawful unreadable profile pages, and by the looks of it this new PopFly thing will allow for custom widget based homepages(possibly pink, sparkly and unreadable) to be created that presumably will include Facebook widgets?