As usual, great stuff from Google.
I don't know how I've missed it until now, but almost a year ago, Google has released this great application called Google Friend Connect (announcement). It's just what I was dreaming about. I believe it must have something (or everything) to do with OpenSocial, Google's alternative to Facebook Platform.
So, what's exactly the point? Let's say you have a website, blog or something like that. Google Friend Connect enables you to add this site social networking feature in just a few clicks. This way anybody who owns Google account can became a part of your social network (website) in just one click.
Yes, it this thing on a right side of my site.