Social networking is not going to take over search. Some people have suggested that facebook will soon take over Google as the number one search engine. The strange thing is however that facebook is not a search engine by any definition of the word.
Facebook may one day have more searches than Google but those searches will be for things related to social networking. Unless however facebook redesigns their homepage to work much the same way as yahoo.
Yahoo’s homepage is a mixture of news, email, and other things, but it is predominantly a search engine. If Facebook took a similar approach and did search the entire web and provided good results then maybe the story will be different. But I don’t see that happening any time soon.
Then again, I am bit old school, so who knows.