Dave Winer posts today about Open Social Networking. It's something we've all been working on for ages -- starting with FOAF back in 2000, continuing with things like XFN and our own PeopleAggregator API.
We're working on bits and pieces of this in PeopleAggregator. The recent 1.2pre5 release lets you display an RSS feed from elsewhere instead of using the built-in blogging tool. Or if you want to keep your blog inside PA, you can edit it from elsewhere using the metaWeblog API and syndicate it out with RSS. You can import friends from Flickr or Facebook, although the protocols for this aren't really standard yet (each site has its own way of doing things) so the UI isn't as convenient. We're also working on a way to run PA behind an existing website, so you can pick and choose features.