Google Dance
Every approximately 4 weeks, in addition to the updates processed by Google's crawlers to index the content of a billion Web pages, Google updates the computation of the PageRank of each indexed page.
This period of update ( Google Dance ) lasts several days, for various reasons:
- the computation of the PageRank of a page A depends on that of all the pages related to this page A. It is thus necessary to leave time to the iterative algorithm to converge.
- once that new PageRank are calculated, it should be distributed on the thousands of Google servers (around 10.000)
During this time, it is possible to see PageRank or the ranking of a page in the results increasing or decreasing. It is called Google Dance. You should not panic, you only should wait approximately 5 or 6 days that all is stabilized.
The most curious or impatient webmasters which want to know before the end of the "dance" how their site rank (or more precisely one of the pages) can do it thanks to the existence of the intermediate bases of Google, accessible by modifying the www from the address www.google.com by www1, www2 or www3 (attention since a few months www1 does not function any more).
In general during the "dance", the intermediate results are accessible on www2 or www3, then to the end they are transferred on the official server www.
We developed a tool allowing to simultaneously search the three www bases, www2 and www3. You just have to type in your keywords and to compare the results:
