I installed OpenID on one of my sites to avoid people having to go through any sign up process and still had people complaining about having to sign up to view it.<p>OpenID is a great idea. But I think it will probably remain as a niche thing used by few enough people that it probably isn't worth the time to implement it properly.
There is nothing more annoying than a company that makes you jump through hoops (complex registration system) to get something that they want from you (your comment, which makes their post/site/life better).