DISQUS is a great service to aggregate your comments all over the web. If you add a comment on a blog / website which is using this system, your comment will be visible in to your DISQUES account as well in post. This way you can keep track of your all comments. Another cool feature is, you can subscribe comment RSS.
For webmasters, It is extremely easy and installed in 5 minutes. There is a plugin available for DISQUS. I recently integrated it into myblog and it took hardly 5 minutes!
Try this and I am sure you will like it!!