Google Friend Connect is a way for web site owners to bring social features like comments or media sharing to any site on the Internet. Today, Google announced that it is also adding support for Twitter to Friend Connect. Now, when you join a 'Friend Connected' site, you get the option to connect your Twitter and Google accounts. This allows you to discover all your Twitter friends who are also members of this site.
To add your Twitter friends, simply go to your Google Profile after joining a site and click on "Add/Remove." You can also choose to use your Twitter profile and avatar as your main profile for Friend Connect. Besides adding your Twitter friends, you can also link your Plaxo and Orkut accounts to Friend Connect.
Sadly, it doesn't look like Google implemented any advanced authentication mechanisms like OAuth for the Twitter integration (Update: apparently this is Twitter's own fault for not supporting OAuth yet, though they promise to enable this feature in the next major release).
As Biz Stone points out on the Twitter blog, this might indeed become an interesting way to find your Twitter friends on other sites. For now, however, Friend Connect is not implemented widely enough for it to have any real effect yet.
Friend Connect vs. Facebook Connect
Google is clearly locked in a battle with Facebook Connect, and thanks to this Twitter integration, Friend Connect now feels a bit more like Facebook Connect, as your actual friends are shown separately from the other members of the site.
This Twitter integration will surely sway a few site owners to implement Friend Connect over Facebook Connect, but it will surely take a month or two before we can see which service is taking the lead.