An article on Wired today mirrors my own feeling on the social network phenomenon. We should not be tied to a certain site to host all our content. The article mentions XFN as a way to show who you know. I've used that for years and a few friends do too, so that it is possible to map our network, but you need to have the right tools. They don't mention FOAF, but that does not show much sign of hitting the mainstream. I first heard about it years ago and have maintained my own file, but it's beyond the technical abilities of many people unless they can auto-generate a file using tools. I have wanted to generate some parts of this site from my FOAF file, but have yet to get around to it.
Meanwhile, my site brings some of my external feeds together via their own web gadgets.
If you have a presence on various services then it is possible to bring them all together using something like Mugshot, but this does not address the point raised by some commenters on the article, that there is no easy way to restrict access to content outside the 'walled garden' of a network like Facebook. There would have to be some form of access control using user accounts, or better, OpenID with automatic recognition of users via the FOAF file. This is beyond my web programming skills for now, but maybe someone else has some ideas.
For those reading the feed, this site does allow for comments, so feel free to click through and leave your thoughts for general consumption.