Stacked open source implementation StackOverflow uses DotNetOpenID , which I think also probably uses itself ...
Although it is built on the WebControls paradigm, so I think that you will have problems with its implementation using Microsoft MVC.
I know Grurrah uses the WebControl -based Ajax library (Gaia Ajax - my previous launch) along with the implementation of the Castle MVC project, but I donโt know anything from the semantics. Although Grurrah is also Open Source, so I think you can easily view its code to check it out :)
This means that you can use DotNetOpenID together with the Castle project MVC library (possibly), and you can go to Ra-Ajax for Ajax (Disclaimer, I work with Ra-Ajax as well as Stacked)
source share