Google - Bigdaddy
By now Google should have finished their massive Bigdaddy indexing. Quite a few people experienced problems on this update. One of Google’s goals on this was to bring together multiple domain URLs that point to the same site so that they appear to Google as a single site. For example:
http://www.netadventures.biz/
http://netadventures.biz
http://www.netadventures.biz
http://www.netadventures.biz/index.html
and even http://www.carltown.net, is an older domain we have that points to our new site.
These are all the same web site on my host. Google sees all of thee as different sites. This splits my PageRank over the various sites, depending on what is used to link into my site. Moreover, Google will try to identify these as a single site, but of these which site should Google use as my main URL?
One of the goals of the latest update is to develop better heuristics to help Google on this. Google has a fancy word for this - the resulting single site is called the canonical site.
For more information see a blog post by Matt Cutts, an employee of Google:
http://www.mattcutts.com/blog/2006/01/page/4/
This is a little old (January 4), but has lots of great information from Matt. As an important technical interface to Google, he can keep you up with the latest. Notice this same blog post (with comments) also refers to to the Google six-month Sandbox.
One thing you will see with this post is a way to help Google know which URL is your canonical URL. It involves setting up a 301 redirect on your host for the sites that aren’t canonical.