So a five minute play with SocialThing makes it seem really promising.
Being able to into easily import all your friends from all your social networks (eventually) and then easily alias them together sounds like it would be awesome.
Sadly it goes downhill really quickly.
Firstly it requires your usernames and passwords. They explain why - to get otherwise unavailable private data (friends only Livejournal posts for example), but it seems unnecessary and phishing-like. What they really need is to do is offer a "publicly viewable information only" option for these services.
Secondly there doesn't seem to be any kind of history. New items push old items off the list and then, poof, they're gone. That's kind of limiting. There's also no feed produced so I can't subscribe to this stuff anywhere else, I have to go to their site.
Lastly you can only see an aggregate view. Having aliased my friends (when I've been fortunate to have two of their posts from separate sites appear on the list at the same time), I can't then drill down to view the activity of just one friend at a time.
Nice idea, but must try harder.