alternative theory....guys don't have any social life....thus on the webz...at least that is my case.
My daughter somewhat does some facebook, pinkbike, powderroom and is considering wolfpack. But is probably more into a varied and speedy chat interaction than a strickly focused forum. And if she needs advice there are plenty of guys to help and give her shit without being on a forum. She does hang with the guys and is often only 1 of maybe 2-3 gals that are in a group of 10-12 guys (skier, riders, dh'llers) and is generally willing to put up with their antics and give them shit right back, willing to go shred/rip and keep up. The other day she went out with 3 guys and did a 4 hour skin to a secret pillow stash...not many women willing and able to do that.
I hazard to say, at the local hill, there are perhaps more percentage of accomplished women riders than at any other hill and they are well aware of the bro/brah thing. But still, the gals that are comfortable with and accepted in the bro/brah thing in any sport are relatively rare and they often have older brothers and were raised or took to being a tomboy....perhaps we ought to poll the gals about this.