Is it possible to use favicons to get a rough idea of the number of people that have bookmarked our site? I figured that we could track the number of downloads of the graphic. Is there another way to do this?

I know that one way that you can track how many bookmarks you get for a particular url is by using the AW stats program. This is available on most hosts in the cpanel section of your webserver. If you look through all the data, near the end of the stats, it says how many times your site has been favorited.