Back in the ‘old days’ of Google and the SEO industry, “Google Dance” was a term used often in the industry. Back then, a “Google Dance” referred to the about monthly updates Google pushed out to their index. Every month or so, SEOs and Webmasters waited for the “Google Dance” to see if their rankings would increase or decrease – yes, this included PageRank updates. Nowadays, you rarely hear about people talking about a Google Dance because Google releases updates, mostly minor, throughout the day. These include index updates every minute and algorithm updates several times per month, over once a day.
Matt Cutts from Google has created a video that explains why Google doesn’t issue typical Yahoo Weather reports, to notify SEOs of an upcoming update.
I should add that the “Google Dance” also refers to the annual party Google holds at the Googleplex for SEOs. This year, Google did not have the Google Dance – so it seems like they have done away with both, the physical dance and the algorithmic dance.