A study by PageLever, an analytics tool for Facebook, showed that search engines are major traffic drivers for Facebook pages, making up 34% of all external referrals. Google was the leading search engine sending 27.57% of all external traffic to pages. This study analyzed 1000 pages, with a minimum of 10,000 fans each.
Surprisingly, Yahoo! is sending Facebook pages more traffic than Bing (who teamed up with Facebook for a more social experience). Google also sends more than 10x of the traffic than Bing. The full stats of the report are:
The median is significantly lower than the average for each search engine. This shows that ta small number of pages that derive a much higher percentage of traffic from search engines, raising the average for the entire sample. Those pages that rank in search are seeing a significant lift in referrals, while more pages fall under the search referrals mean.
In addition to the traditional search engines, YouTube showed it can drive traffic, beating the overall referral percentage of Bing. YouTube had the highest differential between the mean and median. This may be due to the overall lack of YouTube presence by some companies or by the lack of Facebook URLs posted within videos.
PageLever derived this data from Facebook by analyzing the top external traffic referrers from the Facebook API across a six month time-span (Jan-June) in 2011. See PageLever for more details on this study.