@ samsonite: Sorry, no referers. You´d probably not believe where I got the numbers from: Counted them by date on the members list
@ Mars Warrier: I sure love statistics, but this talk started off in a marketing point of view. For this there are far too much stats on your exmple page. Such could be only the basis for one or two diagrams.
I propose to make a decent excel diagram with the forum user development on a monthly basis, so it is not too much work. Works with forum posts too.