You can see this in action right here on the sidebar of Mashable, where you can join our community using your Google credentials. You can also invite other people to join from within the application, either by emailing them (you’ll see a list of your Google contacts) or sharing the links on MySpace or Facebook.
Another example implementation is Qloud, the music discovery service, where you can now sign-in using your Google account, and then be able to save playlists and see which of your friends are already users. Additionally, part of what Google wants to do is allow for simple implementations where webmasters can simply copy and paste code for various Google Gadgets – like comments or reviews – to enable social features.
More details about Friend Connect are available in the demo below: