There's this often unstated assumption that "good" comments will rise to the top.
What about this:
1) Display all comment scores, all the time 2) A new comment is posted 3) Segment the readership somehow, so that the comment has a (possibly different) score for each segment. E.g. Allow a comment to have 4 different scores. 4) Start the comment off with a random score in the range [-2, +2], but one that's different for each viewer segment 5) track (but hide) the number of upvotes and downvotes for each score 6) display just init + upvotes - downvotes to each segment