I have to modify my comments, because after toying around at
wiki.answers.com the voting system doesn't work.
It's the same issue at Knol in general. I get over a thousand "views" a
day of my knols and very very rarely does anyone "vote" my articles either up
or down. There has been suspicion among knolians that those articles with a
high vote count are some form of fraud (for example by creating a hundred
accounts and voting with all of them).
So in order to use the whole idea of "the best articles get voted" to the
top we'd need both a way to combat vote-fraud, and a way to intice readers to
vote at all!
Will Johnson