http://www.google.com/friendconnect/ what do you think? iv added one of the modules they offer to my site, its pretty sweet and would be awesome if it became big. you can check the rating system i added at http://www.psdproxies.com its on the right hand side bar. wasnt sure if many of you had heard about this but it looks promising
Those widgets are only useful only if you have a content site. Those widgets won't work if you have a Community type site like forum/social network.
Google's Friend Connect is a way of allowing the integration of social features to your existing website or blog. It's still in beta, but the idea is that allowing users to sign up for your website with their existing userids from other social networks such as gmail, orkut, yahoo, etc... will bring much higher conversions. It's a big fight between Facebook and Google over this topic right now. Facebook Connect is the "closed" competing service to Friend Connect - there's a ton of info about this over at the Social Arrow, including a WordPress plugin I'm developing to help WordPress users interate Friend Connect.