Sort of reminds me of the ratings system at Slashdot and kuro5hin, both of which are disasters.
Good article by Derek Powazek
here about how Slashdot's originally-useful ratings system turned into a farce as users continued to make it more andmore of a competition to see who could get the best numbers, versus simply bringing something to the table and posting it.
I think that one of the most effective 'ratings systems' that a forum can have is when, like the Rx, "live" threads are continually at the front of a given forum. Although this can be skewed by people bumping a thread up to be silly, spiteful or vindictive, for the most part a thread that gets few views or provokes little response is going the route that it should when it gets pushed farther and farhter to the back (I am embarrassingly aware that this is the case with the great majority of threads that I myself start, but at least I try to keep the flames, misleading subject lines, and gratuitous bumps to a minimum.)
Phaedrus