Google used to update their index quite regularly (in the past this would occur roughly once per month), and as a result, the SERP (Search Engine Results Page) rankings would fluctuate. This was often referred to as the ‘Google Dance’, and would go hand in hand with some panicky phone calls from clients to their SEO companies asking why their position had dropped several places.
Google has now changed to a ‘constantly updating index’ so there is no longer the ‘Google Dance’ occurance.
