I think a feature that enables viewers to make a rating on a post.. & the thread… (kind-a-like in youtube/google groups…) could be very useful, All ratings on all posts of a user could then be aggregated through some kind of a weighted average function (that assigns different weight to the ratings given by different users based on their own ratings as well as evening out the variation in ratings for a user across different times). This may be pretty useful in filtering out useful posts from the not so useful.., give more quantitative insights to mods/administrators when they get in a situation where they have to close a thread. & also since it will add up to the users own rating… it might be act as a self correcting stimuluant for users to be more reasonable.
Anyhow, GS team really good job guys.