Social Network Invitations

So I'm on the bandwagon and am a social media/network junkie. There was a really cool site that I used to use to exchanging invitations with other users, but I can't remember it right now. I've been using another one that's been pretty good and I've gotten quick responses from: Invites.mashable.com

Anyways, I'm checking out SocialThing, Fire Eagle, ....waitaminute...i think i'm following like 10 new ones and i can barely remember them all. Ah, overwhelming.