Just an idea: In order to calculate some measurement regarding how good users find some item, you could not only measure the upvote/downvote ratio of the item itself, but include the upvote/downvotes of the comments. People who find some item noteworthy also tend to comment on it - or at least that's my hypothesis - so you'd measure not only how much people like an item, but what others have added to the original item, and how much others value this addition.