In the middle of May 2011 Microsoft announced that Bing will start using Facebook Likes to help determine their search results. The week after this announcement I noticed my traffic from both Bing and Yahoo dropped by ten percent. My Google traffic remains pretty stable.
I checked my rankings on Bing and it appears my site has retained its ranking, but I've lost a significant amount of traffic from this change. I think part of the problem is when you log into Bing or Facebook and use their search they displayed more ads at the top of the page and this pushes the natural results down lower than they previously were before I signed in.
I also noticed when you use the Facebook search it uses Bing's results, but it only shows the top three with an option to see more. If you want to see more you will leave Facebook's site and go to Bing's.
This is very disappointing for me, and I think will be for many other small website owners who receive traffic from these sources. Before this change I earned a record amount of money from my website in May. Now with the less traffic I am getting I will be lucky if my June earnings equals Mays.
I think my best way to continue to grow my traffic is to focus on adding more and more content and reviews each month.