Earlier quoted context omitted.
Most people's social graphs are too small (130 people) to be useful. Well we will use an extended social-graph, you might say, but if you are extending the social-graph, why not include the entire internet? Why would my social-graph contain better (more accurate and relevant) information about doing a thing than doathing.com? The social-graph is a reduced set of the internet. It is probably easier to search, but how…
I think you are mistaking how to integrate the social graph into search. You don't do it by exclusively searching within the social graph, you use the social graph to augment your traditional search. The best way for me to show you what I mean is for you to look at the attempts blekko is making. Create an account, and connect your facebook profile, wait 1 hour, and then do searches with "/likes" appended. You'll stil…
With Google's velocity, I think they're probably going to get to "social search" first (good luck to Blekko, but reliance on FB is not going to scale - especially when FB looks to monetize - social search is their meal ticket).