Commentful – Tracks Blog Posts and Comments
http://commentful.blogflux.com/

Commentful is a service that tracks blog posts and more and notifies you whenever a new comment has been added. You simply add any URL to your Watchlist, and we do the rest. This has been added to the tools section of Research Resources Subject Tracer™ Informnation Blog. This has been added to Business Intelligence Resources Subject Tracer™ Information Blog.