www2.google.com + www3.google.com

[Rusher]

Anyone know why the www2.google.com and www3.google.com servers exist?

[suwunk]

Whilst nobody outside of "Google" truly seems to know the purpose of the www2 & www3 servers, many people have come to the assumption that they are test servers. During the update, which takes several days, the 3 Google servers display different results. Whilst the results vary from server to server, they are said to be "dancing", hence the name "Google Dance".

Source: www.seochat.com/googledance