Ian Brown continues to add features to his proof of concept InfoCards for Safari, and has software that will definitely get you into my blog to leave comments. He points out that his identity selector still needs a number of features, but as Jon Udell has said, Ian's work is absolutely cool. It's not taking anything away from Ian's accomplishment to say it should inform everyone's thinking about the fact that there is not a huge barrier to entry for this technology. It can be deployed cross platform, and is eminently buildable. To quote Ian:
For the faint of heart, or for those running those other operating systems, here's a short screencast of the selector in action, authN'ing against Kim Cameron's RP
Download the plugin for the Power PC here.
Download the intel version here.