Is this "a guy thing"?

My neighborhood newsblog, My Ballard, has a post about two local men who started a weight-loss competition that turned into a website.

At FatBet.net ("you bet your ass") you and friends can set up weight-loss challenges. Your actual weight is kept private; members of your group can see only the amount you want to lose during the challenge time frame.

I'm wondering if (and hoping that) they'll expand this concept to cover fitness challenges (miles biked during the summer, martial arts levels attained, miles walked per week, etc.).