Bones - 12:11 am on Dec 24, 2006 (gmt 0)

Common Words: Our prioritized listing of your site's content The common words feature lists in order of priority (from highest to lowest) the prevalent words we've found in your site, and in links to your site. (This information isn't available for subdirectories or subdomains.)

Anything to do with that perhaps? (from the webmaster central blog).