When there is any of changes in website page rank and it's positions then that position called Google Dance. It's happen many times in a year, but after some days website position adjust like before. it's a technique of search engine optimization to check quality of content frequently. and for more info regards same go to seo-first-page.com
Google Daily updating is database so during the Google updates, SERP of your site is also changing that called Google dance.
daily to daily shuffling of keywords at search engine (Google).in the terms of it is called a Google Dance....
Google never describe such thing or word! people just thinking themselves, Google Dance is really not exist.
In search engine optimization (SEO), Google Dance is an out-dated slang term used to describe the period of time in which Google used to rebuild its rankings, and as a result of this rebuilding, rankings of Web sites on Google's SERP may fluctuate in order during a several day period. The "Google Dance" would happen anywhere up to 36 times per year, however in 2003 Google begun updating its index on a weekly basis, which all but eliminated the Google Dance.