I used to spend my day managing email. Then, it was RSS feeds. Now, it's trying to stay current with friends in Facebook, Linkedin, Explode, Elgg, Twitter, and, occasionally, friends in real life. I now have the joy of filing out profiles with each new service I join. Decentralizing friends, relationships, and knowledge is great. But I prefer to have my ID centralized. It's like database redundancy. Why not just keep unique data in one place? If it's repeated in numerous locations, accuracy becomes an issue. One profile, fed into many systems - seems simple.
While not quite what I'm looking for, the challenge of following friends from other sites can be attended to with Loopster: "Loopster enables you to import your friends from various social networks, connect them together and watch how they change." While that's great, soon I'll need an aggregator to aggregate my aggregations. Then I will be fulfilled. Until the next iteration.
TechCrunch lists a few other options for profile management.