Have you seen the ability to use your facebook login to comment? I saw it on the CNN site the other day. This will be the wave of the future, since most users already have a facebook account and don't want to create a new account simply to post a comment. Lower the threshold and you will get much more interaction. I found I can even implement facebook comments with Joomla. The hitch? Right now the system is a bit fat. Pages take a bit long to load.