It seems all of Facebook's fears regarding Google's "Search Plus Your World" have been confirmed...maybe.

New stats on referral traffic to Facebook from Google were recently released by a Facebook analytics company called PageLever. The news site Search Engine Land first reported this data. The numbers show that ever since "Search Plus Your World" launched in January, Facebook's traffic has taken a nosedive.

What's strange, however, is that referral traffic from Bing is also down -- and obviously Bing doesn't use "Search Plus Your World."

Google rolled out "Search Plus Your World" five months ago, much to its competitors' chagrin. The way the service works is by customizing search results and integrating content from Google Plus into users' queries. Alongside the searches, users are provided with "relevant tips, photos, and posts from your friends."

At the time, many social networks cried foul and claimed that "Search Plus Your World" was one step further in Google's quest for Internet domination. Facebook and Twitter argued that Google was propping up its social network while lowering the quality of its search results. Some of those social networks' engineers even created a browser bookmarklet tool to add results from Twitter and Facebook into Google's search results.

What PageLever has found since "Search Plus Your World" hit the scene is that Google traffic to Facebook pages has dropped 51 percent. Studying 500 Facebook fan pages with at least 10,000 fans, the analytics company looked at external referrals from Google and Bing. Before January, Google drove an average of 9.25 external referrals per fan page per day to Facebook and now it drives just 4.52.

Bing's referral traffic seems to follow a similar trend -- dropping by a whopping 59 percent from 2011 to 2012.

So is "Search Plus Your World" to blame? The answer is unclear.

PageLever's co-founder Jeff Widman points out that Google's referral traffic to Facebook actually began to mysteriously fall off three days before the January 10 launch of "Search Plus Your World."

"Referral traffic from both Google and Bing to Facebook Pages started dropping on January 7th. That's three days before Google rolled out SPYW," Widman told CNET. "The timing is certainly suspicious, but it doesn't explain why traffic from Bing plummeted as well."

Here's a graph from PageLever:

PageLever

This story was updated at 12:46 a.m. Thursday, May 31 to correct traffic data. Instead of driving an average of 9.25 "percent" before January, Google drove an average of 9.25 "external referrals per fan page per day" to Facebook and now it drives just 4.52.