dillinger - it used to do that
nowadays it has been used by Google to kinda mislead people that were using it for buying backlinks - it really doesnt mean all those things anymore
Its a shame too as it used to be such a good way of measuring pages changes - now you basically just have to watch the ranking in the index - another way you can look that still works is to look in the Google Directory - they still show a "relative PR" green bar in there next to the category listings that is a little better and accurate - the difference being that the green bar in the directory is split into 40(if my memory is still good LOL)divisions wheras the green bar on the toolbar just has 10