OpenID is basically an attempt at single sign on. In theory you’ll be able to go to any site and log in or comment without the need to remember 31 passwords and user names.
So far it’s working great. I have it setup so that I just have to type in my blog’s url unbeknownst.net, it remembers my password, and I can log in and comment at a growing number of sites. My next goal was to add my blog to said growing cadre of OpenID compatible sites.
The best option currently looks like the WP-OpenID plugin. It was a pretty straight forward install but for some reason it was giving me blank pages when I submitted a comment at first. Seems to be humming along now. Feel free to try it out with your OpenID if you dare. I’ll leave the first comment using my OpenID account.
I allow anonymous comments on this blog so it’s not a big deal but you do get to bypass the spam filter if you’re using OpenID (at least for now).
* Update: Delegation doesn’t work. On other sites I can use my blog URL to log in but this plugin won’t let me do that for some reason. I’m sure they’re going to fix this in an update one of these days.