Footbag.org is not a web space for kids to hang out on. It's a serious information site with a huge investment in time, money, and equipment to keep the world of footbag together.
Private Messages ("PM"s) are a way to enable kids to use the forum as their home base, and lets people become unacceptably lazy with updating their e-mail address on their member profile.
E-mail is the foundation of our identity system on footbag.org. We require every member to have a valid, functioning e-mail address. If we discover e-mail is bouncing for a given user, we disable their accounts until they re-set their e-mail to a working address.
Because of this, it's senseless to enable people to communicate and to use their footbag.org accounts without having a valid e-mail address. If you can't get an e-mail address in this day and age and keep it for a while, that means we can't keep track of you, and thus we don't want you using our service.
Since every member of the forum has a footbag.org member name, and since we forward all e-mail sent to firstname.lastname@example.org to each person's real e-mail address, there's really no point to having PMs. Just use e-mail.