Hey Suelin23, thank you for your comments too. Yeah, maybe my question was a bit esoteric, or I was taking too literally the 'define a game you can win' premise. IOW, I was expecting a project formulation that did the work for me! So I'll stick to the traffic rate as measurement of success. I guess there are certain situations where all you can do is doing your homework and hope for the best.
As a sidenote, I wonder, perhaps visits to a website is one of the hardest things to foresee; in the sales example, at least, one has prediction models, market trends, but information consumers do as they please, don't they? (Unless, I guess, one sticks to mainstream, dull contents a la 'Twilight', 'Paris Hilton', etc... but that would be a no-no in my principles list).