I like this idea. As another commenter pointed out, we seek out external validation (whether we like it or not). However, there's good and bad kinds of external validation: looking for popularity (total number of upvotes) vs. more direct feedback from people you respect (Kuro5hin model: a score with a name attached to it) works better. The fact that a comment would be rated rather than voted on Kuro5hin (with a maximum rating) also has the capping effect.