hello i think "Google Dance" has often been used to describe the index update of the Google search engine. Google's index update occurred on average once per month. During an index update there was significant movement in search results and Google showed new backward links for pages. However, in mid-2003 Google started to update it's index continuously. It appears that, still, there has to be an update of the complete index once in a while and during this time new backward links are shown. But, because of the continuous update, the effects on search results seem to be rather insignificant.
We will keep this site up running because it provides some information beyond the Google Dance. But there will no longer be a monitoring of updated data centers during a "Dance".