Seems to me the thumbs-down function is useful for application to posts that have nothing to do with the topic, for those that are only insulting weak-ego hissy-fits between posters, and/or things like outright racism etc. Better than anything similar to censorship.
Thumbs up for agreement with post.

I agree but I won't give you a thumbs up or down. This function is useless. Where's the spam button. I've been asking for since 3 years ago.

@ liumingke: If you agree, why do you say it is useless?
Seems to me spam should be dealt with by gokunming - such a button could well lead to legit posters disappearing posts that they didn't happen to like.

I meant I disagree. :-).

Sorry, thumbed down when I wanted to thumb up. Apologies. I'm on the phone and my thumb was too fat.

I think its a good idea but some sensitive souls obviously consider it a personal affront to their empty insights.

And as you mentioned it can save me from reading through drivel, unrelated posts and posts that are offensive, and can be used to hide spam.

The days of threads attracting 20 and more pages, most pages past number 4 containing self-indulgent one-on-one arguments, are largely history.

If thumbs can be proven to have contributed to this improvement, then anyone advocating their demise should offer an alternative that will achieve a similar result. On one occasion, as far as I've noticed, thumbs have 'censored' one alternative but unattractive point of view. That's unfortunate.

@ nnoble: Not sure if threads you mention are really history. I didn't know that a certain number of thumbs-down could 'censor' (you mean remove?) a post - I don't think that's good either, but otherwise the thumbs function makes it easier to protest hissy-fits etc. and make it unnecessary to get into a long one with the offending poster, which will likely produce another post of the same nature - anyway, what alternative? The thumbs-down doesn't bother me and I read whatever I want to.

It certainly has reduced the hissy fits, and as pointed out, you can show what you think of a post without getting into a 'long one'. It already seems to led to some more considered and contributory posts, which can only be good.
Even three thumbs down does not remove the post. You can still view them if you want, as such it isn't censorship; but is a clear signal to the poster. Yes there will be the odd post that gets thumbs downed and hidden, when perhaps it shouldn't. Unfortunate, but one post in hundreds is really no consequence, nothing posted on here is ever life shatteringly important.