I've begun work on adding support for Open ID and also for Windows Live ID in mojoPortal. I hope to have both fully working and committed to svn by the end of the week.
The Web has long needed some kind of single sign on solution and I am glad to see solutions like these available. The convenience for users is that sites that support these authentication services will be able to let users register and login without having to create yet another user name and password.
In mojoPortal, these will be supplemental authentication methods that can be enabled or disabled at the site level. They will work in addition to the regular email-username/password scenarios. Windows Live ID requires getting a Windows Live Application ID and Secret Key for your site so I have already added a place for this in Site Settings.
For the Open ID support, I'm using DotNetOpenID, and for Windows Live ID I'm using code based on the samples in the SDK.