I was searching about looking for some info on the Google toolbar.
There has been a lot of discussion about any info it phones home to Google with. It has been suggested that Google may in effect use this for discovering new content.
It appears that the toolbar sends an encrypted message to Googles servers whenever a get request is sent from the browser. The message contains the URL and client (toolbar). If you can imagine the Google bar as a browser. It sends a request to Google and the Google servers send a reply. The reply is an XML file that tells the bar about the current documents page rank info and also the category if any that it resided in the Google directory. The request is made to google.com under the following query…
Info:http://www.whatever.com and from here the bar is able to offer the page info selections.
Hope this was of some use to someone.
