I've found that co.mments is a little "prettier" and easier to use. Maybe it was that Firefox plugin issue with CoComment. With both services, I believe it was possible to get a feed of all comments to the entries I had explicitly tracked. I find this a great mechanism for seeing what new things people say on articles in which I have specific interest.

Another way to track these comments is to use an Aggregator that can read individual-article comment feeds. My aggregator (GreatNews) and a few others give you the ability to easily subscribe to the comment feed for an article.