Google
Update Pattern From
Ever since the last Google update in late June, there has been wide speculation whether there would be any more "Google Dance" updates. As you recall, the "Google Dance" was about a 4 day period of time occurring about every 30 days when Google updated their entire index and SERPs (Search Engine Results Page).
After observing Google for a little more than 2 months, we can now report that Google is now conducting a "rolling update". Position Research has plotted Google ranking movements for more than 60 URLs covering more than 500 keywords over a 60 day period of time. Three general observations can be made.
Incremental ranking movements were observed about every 4-5 days. These observations were most prominent in campaigns that were young and had ongoing link optimization efforts. Perhaps Google was incrementally attributing partial value from newly crawled links.
Large ranking movements took place within a 25-30 day period. Google backlink counts changed within 5-7 days following.
Different websites seem to be receiving their large ranking movements at different times. Although difficult to tell, there appears to be evidence to support an Alpha sort order (e.g. URLs starting with the letter B receive large ranking movements just prior to URLs starting with the letter C). Since this observation only applied to young campaigns where large movements could be observed, the sample set was small and was not statistically significant (a fancy way of saying it could be coincidence).