The gravity figure in itself never did much for me. Yeah, you could tell if affiliates were promoting one product more than another and that could give you an indication if you want to promote the same product yourself, but that is a matter of preference. And one guru will tell you one thing while the other will tell you something totally different. And who gives a crap about gurus anyway.
But a site like CBtrends that has a listing of past gravity values has some use. You can watch as other affiliates jump on board with exact figures. To me, with at least gravity, this is worth more than the graph.
I am still trying to work out a formula to calculate a guessimate of actual sales volumes based on the figures that Clickbank gives out. Stay tuned for news.