I did a search and found no references to Cardspace.  I take it there are no plans to implement a Cardspace sign on and registration facility. Since its relatively simple to implement and it's Microsoft and it would make the process of registering and logging in a dream, why isn't there anything on Cardspace given the close relationship between DNN and Microsoft and the fact that every Vista machine and any XP machine that has Framework V3 runtime installed has Windows Card Space in their control panel.

Check out this video from Microsofts Chanel 9 and see why Card Space should be standard with DNN and not a Snowcovered module (No CardSpace products at snowcovered yet).

http://channel9.msdn.com/Showpost.aspx?postid=306082

Seeing is believing.

MS have a site for this technology;

http://cardspace.netfx3.com/

There is a great video on cardspace which takes you through adapting your site to Cardspace. Also excellent documentation.