I like the Facebook redesign. In particular, I like that my feed now consists of two-way conversations between friends, rather than mostly one-way sharing of photos and profile changes. I used to get my conversation fix from FriendFeed, but early on in the site's evolution, friend-of-friend strangers got added to my feed and the signal to noise ratio became too low for me.
I've been seeing around the blogosphere reports of haters for the new Facebook UI. Much like every other redesign, there is an anti-redesign Facebook group with a million people, etc. I want to know the actual pulse of the people, and whether the dissenters are a vocal minority vs. widespread! I want to go to a site and see a clear percentage breakdown of who likes it vs. hates it.
In general, for any controversial issue that I'm curious about (abortion, gay rights, No Name Cafe food quality), I want to go to a site and see the pulse of public opinion about it.
I hope one of these prediction market sites will take over and become used by everyone, to satisfy this purpose. I've seen them used within private contexts, and they were very effective in showing what the crowd thinks.