Actually, one of the biggest Russian IT social news sites (habrahabr) has this for quite a while - you can't see a rating of article until you vote (up, down or "zero", but you can't upvote or downvote if you vote "zero", you just get to see the rating). It's working pretty well ever since it was implemented.
On the contrary note - bash.org.ru, which is kind of a clone of bash.org, tested this idea, but then they got back to showing the rating beforehand.
Yep, but bash.org.ru did not give you the option to just see the score without voting. Given how high the trash / not trash ratio is there, I think it's only reasonable that many people wanted to see a quote's score before reading it (and upvoted the quote to see it).
On the contrary note - bash.org.ru, which is kind of a clone of bash.org, tested this idea, but then they got back to showing the rating beforehand.