Google is trying to keep their servers from crashing. An invite is USELESS right now. I got one yesterday and I STILL can't gain access to Google+. It would be funny if everyone just gave up on Google+ and by the time they fully open the doors they find themselves in "myspace status" as in "no body cares anymore" :wink: But that's not going to happen. I'd like to check it out but I'm not freakin' out about it because even when I do get in it's unlikely that most of my friends will even bother checking it out any time soon.
I wouldn't say it's useless. I'm in and it's pretty cool just to see what its capable of. The Circles and the Sparks thing make it better then Facebook for me tbh.