Google slap
n.— «When your ranking drops, 90% of the time it’s because of a SE changing it’s methodolgy for ranking sites. They are doing this because they believe it is in the best interests of their users. Some people refer to this as moving the goal posts, others refer to it as a “Google slap.”» —“Search Engines And Your Website” by John Harrington Photo Business News & Forum Sept. 26, 2008. (source: Double-Tongued Dictionary)