I've always wondered why someone hasn't created what I call the 'orange slice' expression button. Much like cutting an orange in half it gives a preset amount of positive and negative values. Sort of a play off the meta moderation that Slashdot did.

For positive values it you could have something like

[I believe this is truthful], [I like this content],[Funny],[Positive message]

and for negative values

[I believe this is false/untruthful],[I dislike this content],[Sad/hateful],[Something else negative I can't think of at the moment?]