That'll work great if you're searching for the latest hamster-on-a-piano video. It might not work quite so well if you're searching for something with substance. Despite the hype, most people aren't especially good at uncovering original content.

A totaly agree, people don't usualy share much stufs on facebook? Have you seens around a link to a Hadoop tutorial in your news feed yet?

I think that sharing that sort of thing will be in a more targeted way, via e.g. yourpane.com. I never share links that don't appeal to everyone on Twitter or Facebook, but I send things to specific friends all the time.

You could, but I doubt many would use it. I agree with the above, that people compartmentalize, and they see Facebook as a place to see pictures of their friends and play games. They see Google as place to look up information.

There already is a very good search on Facebook and the fact that it is powered by Bing is unknown and irrelevant to 95% of the people. However it hasn't made a dent in search, so you have to seriously ask why that is. If you believe in Facebook as a search engine (I don't), the only real answer is because it's not powered by Likes. But to believe that, you have to believe that people have a major affinity for Likes, enough to throw away their old search habits in favor of it.

I would see the fact that the walled Facebook encompasses more and more of previously searchable content as a bigger threat to Google search. Facebook that cannot be scraped for content competes for the pageviews share with the independent searchable sites, so there's less left for Google to search.