Google Dance


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Currently, there is a continuous update of Google's database that is called Everflux by Google's engineers. According to this method, an update of the Google search results is performed on a daily basis. In Israel (meaning on google.co.il), this update usually occurs during the small hours of the night (between midnight and 4 AM).

Up until the summer of 2003, Google's database updates were performed only once a month and big updates received the name "Google dance". This kind of updates no longer occurs. However, there are some updates that Google performs once every few months. Currently a three months cycle that Google started using can be recognized, of one update per month (usually at the beginning of the month):

Visible Pagerank Update
This is an update of the pagerank that is displayed on Google's toolbar. It is important to mention that the update is of what is displayed - internally, Google updates the pagerank regularly for use of it in displaying search results.
Update of Google's Directory
Update of the Google Directory, which is actually a copy of the dmoz.org index.
Inbound Links update
Update of inbound links that you can see with the link: command on Google search. It is important to mention that the visible links are only a subset of the total number of links! Google displays only a sample of the existing links.

The above actions do not always occur in the same order, except for the PR update that occurs every three to four months.

Google Updates List

A tool for tracking the displayed pagerank update:
Future PageRank Tool

A tool for tracking inbound links (backlinks):
Backlink Update Tool

A change in Google's search algorithm - Google Dance

The old Google dance is replaced with a new kind of a Google dance - the algorithm change. Since every Google dance of this kind leaves behind many websites that the new change caused them to fall down the search results, each Google dance receives a name that is similar to these given to hurricanes by the ABC's, each new year the count restarts from A. For example, the first dance in 2005 was called Alegra (a dance that occurred on February 2nd, 2005), and the second one (May 20th, 2005) was called Bourbon.

Some technical background

Google's search engine structure has over 10,000 regular PC computers that operate on Linux. The computers are divided to a great number of Data Centers that are distributed in the USA and Ireland. Each Data center has its own IP.

When you type in the Google address in your browser, the address is translated by the DNS server of your service provider to an IP address. Usually, the DNS server keeps the IP address that it received for additional use for one or two days. Keeping Google's IP address is permitted for 5 minutes only! The result - every five minutes the DNS server of your service company has to search for Google's updated IP address.

Every time that a DNS server checks Google's IP address, Google returns an IP address of a different data center, so that for every search performed, the search will reach a different data center. This way Google scatters the required search power on many computers, thus lowering cost.

When a Google dance occurs, the update is distributed to one data center each time. The distribution of the update to all of Google's computers takes a long time, and this results in different data centers operating with a different database: identical searches that will reach different data centers, will produce different search results. The result looks like Google's search results are "dancing". This dance may take a while, for example the Alegra dance (February 2005) that lasted over a month.

Tracking the Google dance

The first sign of drastic changes in search results excites the site owners' community, which then starts tracking the dance process, and checking which data centers are already updated, and which haven't been updated yet.

Tracking Tool for differences between Google's data Centers:
Google Datacenter Watch Tool

The Florida Google Dance

As of November 2003, significant changes in Google's search results began to show up, to which professionals referred to as the Florida Google Dance. It appears that this dance included significant changes in Google's search algorithm in addition to the regular updates, and opinions vary regarding what changes were made.

Some claim that one of the changes that were implemented during the Florida Google Dance is the HillTop algorithm.