The only thing that worries me about the voting functionality is how this will work in regards to SEO - specifically people spamming with votes for less relevant search results in their various niches. I have no doubt that this kind of voting will work for broad terms, but would be less valuable in very specific keyword phrases which only get few searches.

What would be fantastic is if Google could weight these votes based on how "alike" the person voting for it is to me.

EG, if I was interested in say, Kung Fu and Knitting, and there were other people interested in Kung Fu and Knitting, then the options that they vote for would be more relevant to me than someone who was doing SEO work on those various sites. So hopefully those would rank higher.

In the video, he shows that comments too can be voted up and down (not just search results), so bad comments will quite quickly disappear.

Comments should be from your friends, like friend feed.