i've added the ability to see a history of how problem ratings were calculated. (i've also improved some of the fluctuation). you can see it by clicking on a problem's difficulty popup, then selecting "rating history" from the bottom. here's an example from a recent problem (the data has only been collected recently):
http://www.goproblems.com/prob/ratinghist.php?id=17266
Problem rating history
Re: Problem rating history
Nice. It does not work in IE8 but does in Chrome and FireFox.