Deep crawl&google dance

Once a month, Googlebot will crawl all of the links it has listed in it's database on your site. This is known as the Deep Crawl.


Once a month, Google performs "The Google Dance" using results it obtained from a "deep crawl" of your site. During this update, which usually lasts from 3 to 5 days and starts around the end of the month, Google recalculates your sites PR (PageRank), back links (the number of sites which link to you), and in some cases, recalculates where a given site appears (ranking) in the Search Engine Results Page, AKA "SERP