That's a good perspective, thanks. It's looking really promising.
I still wonder how I can inform a social search that I'm "me at work" -- i.e. I'm more interested in what's popular with Hacker News users, not the people I jibber-jabber with on Facebook. I'm constantly searching YC comments for any technical subject.
I don't really look at likes data as improving the quality of my search. I think of it as asking my social graph what their opinion is. I expect that to tell me what's popular, not what's best.