This is an excellent video on OpenID. One of my biggest take aways was the point Simon Wilson makes about OpenID being, I'm paraphrasing , a point solution to a particular problem, that in some ways is like the Unix OS, in that the solution can be extended in unforeseen ways in the future. This contrasts with the comprehensive approaches also available.
http://video.google.com/videoplay?docid=2288395847791059857Â