Despite only being mentioned in passing on their site, The Guardian broke down some statistics on their commenting community. "At least 20% of the comments left on the Guardian website each month come from only 2,600 user accounts, who together make up just 0.0037% of the Guardian's declared monthly audience. The other 80% come from a maximum (mathematically calculated) of 498,600 accounts, or 0.7% of the total monthly audience, broadly reaffirming the 90:9:1 rule. (At least 80 of those 2,600 are on the Guardian's Technology site"
The affirmation of 90:9:1, or the one percent rule, is a vindication of many assumptions people make about forums and comment sections. Looking at this you can assume that comments are either a service to the most ardent followers of your site, or it can be simply a vocal minority that can bully you into group think.
That depends on the site of course, and it depends on the writers' relationship with with those commenters. Trying to build a community isn't easy work, and understanding the makeup of that community is important. The Guardian shows comments are given by a small user base, and it may not be rise to assume those inns hold for your whole audience.