WordPress blogs and the new blogger blogs (with page elements) provides comment feeds along with the post feeds. So if we wish to read the comments of any blogs using our feed reader, we just need to subscribe to those feeds only.
The advantage of this method is that we won’t be lost in the flood of comments from various “unknown” and evergrowing list of blogs.
The disadvantage of this method from the present method is that we might not be able to know about the new discussions and rumors in the blogs.
You can use Google Reader, Bloglines, Thunderbird etc as the feed reader.