Aggregating your social network presence

The b-side blog provides a useful review of 20 social network aggregators on the grounds that

social networks aren't helping us organize; since all of them require different credentials to log in, they're just adding to the noise.

I have to confess that it's not clear to me, so far, whether the aggregators aren't just adding to the problem - spreading our existing social noise even further afield!  Perhaps I'm doing something wrong?