Not to sound too evangelistic, but I've been using Google+ -- a social network to battle Facebook, and perhaps Twitter -- for just over a week and it's changing how I interact with new and old friends and contacts. The key, I'm convinced, is getting enough people in your circles who are past the "gee wizz" phase and actually use it. That took a shockingly fast three or four days.
Now that bunches more people are inside, and Google is able to keep the invitation windows open longer, it shouldn't be so hard to get an invitations. But that's easy to say if you have one. (And the rollout for people who have Google Apps -- don't worry if this isn't immediately familiar to you -- is delayed.)
If you don't have an account and want one, ask me in the comments.