Facebook could capture around 22% of the global search market, according to the London-based digital marketing agency Greenlight. The results, released in a survey of 500 people, revealed that only 5% would 'definitely' use a future Facebook search engine to rival Google's. That compares with 26% who said they would not. For now, Facebook relies on Bing to power searches on the site.
They have a lot of work to do if they go this route. Facebook has the single worst search function I've ever seen, it doesn't even work to search within their own site!