Since co.mments.com shut down I've had to find a new site to track comments to blog article that I have commented on. It turns out that the two alternatives both suck, for different reasons.
Cocomment requires a firefox add-on that is fairly broken. It wants to track every comment page and the only way to not have it track a page is to right click on the cocomment icon in Firefox and disable it, then refresh the page. Annoying. The other problem is that it doesn't work on Drupal sites. When you try to submit a comment on a drupal site it will not work and you will be taken back to the submit comment page. Luckily Firefox won't clear the comment text box so your comment won't disappear. The only solution is to disable Cocomment on that page and refresh. The bigger downside is that my comment won't be tracked. The only upside to Cocomment is that the RSS feed does work. I don't particularly like the web interface though, it's too messy and overly complicated with little icons whose use I always have trouble remembering.
Commentful is nicer and works more like co.mments.com. You're essentially just submitting a URL to a web service that will then notify you when more comments are added. The problem is that the RSS notification feed doesn't work. Not only that, but when you go to your watchlist, you have to click on the little "Check" icon for each item in your watchlist. That's right, Commentful doesn't even check the websites for new comments unless you ask it to. I suspect they didn't have enough resources to be checking remote sites every 15 minutes so they disabled that altogether.
I'm really tempted to write a Django application to do this. The only challenging part is determining how many comments there are in a blog article, and being able to do that across many different blogging platforms (wordpress, blogger, drupal, custom sites, etc...)