So far this has only really happened on two of my sites. The first time happened about 5-6 months ago, a site of mine got 200+ hits from Bing all of a sudden for 1 day. Then the next day nothing, and ever since... nothing. The second time started about 2 months ago. Another site of mine started getting 300-400 hits a day, then down to 100-200, and now... nothing. It's bizarre and I don't know why it happened. Also, does anyone know how Bing reshuffles their SERPs? Does it take weeks to months like Google operates, or is it completely different?