Is there a subtle privacy problem here?

I was looking at the demonstration of how socialthing will allow you to alias together your friends various accounts into a single entity. It's a useful enough feature, and probably something I'd want to do were I a socialthing user.

However, something about it makes me subtly uncomfortable. I might know that my friend Bob is bob123 on last.fm and bob1974 on Twitter. Does that automatically mean it's OK for me to announce that to the world? Maybe Bob doesn't want that link made public and specifically chose different usernames for that reason.

It's not a big thing, but I'm not sure it's my place to aggregate information about someone else.

The caveat here is that I am not a socialthing beta user, so it's entirely possible that this aggregation is for personal use only. The video doesn't make it clear.