The Google Dance is a term that’s been around for many years and it refers to site rankings jumping about all over the place. In the early days of Google is was often due to the index being at a different version at two different data centres. A visitor would search for a term and get a set of search results based on the index in Data Centre 1 and when they revisited Google and searched again they would get a different set of results because they had hit Data Centre 2 and this had a search index which had been compiled at a different date.
Recently people have been noticing a different type of Google Dance where they launch a new page and it ranks highly initially and then it disappears from the index, later it comes back again. Although this seems strange, it’s normal behavior. The reason for it is that Google is optimising its results by seeing how people interact with your new content. If the new content suffers high bounce rates, low engagement rates and receives little interest from social communities then it’s likely that its rankings will dwindle. Conversely, if it achieves high levels of engagement and scores well in terms of it’s digital footprint then it could rise.
Here’s an interesting video from Google Webmasters where they discuss this form of Google Dance.