I personally think we'd get a lot of duplicate comments stating the same thing which would reduce the overall quality of the topic at hand. An example that proves this is Ebay's user reviews. You have a lot of people participating in reviews because it's a review system that works both ways, so it's in the both user's best interest to review and rate. But most reviews are duplicates.
YouTube's comment system, which has a younger audience mainly, is rife with spam, trolling and comments that add nothing to the discussion. Is this what we want everywhere? Are those people outliers too? Or people with more spare time than people who purely browse?
I wouldn't use the term "outliers" then to describe these people. I would simply call them "people with initiative"... And in some cases "people with initiative who also want to help".