OK. This is genuinely beginning to drive me nuts. This whole "people vs. algorithms" thing. This whole "social vs. search" thing. News flash, blogosphere -- it has always taken both people and algorithms. It has always taken both social and search. Google is much more like Facebook than it is different.
What does Google do? They:
a) analyze links on the web. Who put those links there? People. What are those links equivalent to? Recommendations.
b) analyze user behavior (clicks) within Google, which is a lot of clicks. Who does the clicking? People. What are those clicks equivalent to? Recommendations.
Here is the singular brilliance of Google: Unlike all the great data-driven marketing companies that had come before them, they figured out how to bootstrap this giant people-driven recommendation system using someone else's data. Free data. Public data. It was all just Out There on the Web, and they went and examined it, and said, "Hey! All these people are implicitly making recommendations with their hyperlinking habits! We could USE that!"
Previously, you had to have inside information to assess what people thought, what they wanted, what they recommended. You had to work hard and spend money to collect that information. On a small scale, like Zagat. On a big scale, like Nielsen. On a giant scale, like FICO. Do you think Proctor and Gamble wasn't driven by the preferences and recommendations of people in 1950? Of course they were. But they weren't sharing. Google grabbed the brass ring of the web, leveraged it up into their own highly trafficked search engine (and its highly proprietary set of consumer data) and now, they sit at the center of a set of human recommendations -- clicks, blog posts, hyperlinks, ad buys, domain name purchases, etc. -- the breadth and richness of which boggles the mind, and turns Facebook green with envy, their considerable bravado notwithstanding.
Two years ago, I wrote a post about the different ways that users express their preferences. Then Nivi said it better than I did. Nothing has changed here -- and search and social are still much more similar than different, and Google remains the greatest and most profitable people-driven recommendations company on the planet.