so i've updated the site with a new rating system for problem solvers: you start at 30 kyu, and work your way up as high as you can by solving new problems. i think this should be fun as well as educational.
let me know how this feels for people -- and if the ratings seem appropriate for the difficulty of the problems.
note: your old rating graphs were based on a different starting point. they now start at 30 kyu.
(this is using the Elo rating system for both problems and users.)
Interesting fact, - if I edit a problem or look at the comments without solving it first, - my rating goes down. So, in order to fix an invalid problem, one has to sacrifice his rating. No wonder I'm still a 31k.