OpenSocial
So, there's a new social networking API in town, OpenSocial, from Google and a bunch of others (most notably MySpace). From the brief reading I've done of the documentation, it looks like it's based on Google Gadgets. Apparently documentation is not yet available for the 'container' side of OpenSocial, unfortunately, although it's probably reverse-engineerable. Dave Winer makes a good point: this is probably because Google doesn't want to freeze the spec just yet.