I dont see the problem. Art Directors and others looking for talent are either used to sign up for lots of pages, or they can not be very serious. Renderosity is perhaps the biggest community for 3D artists and I seriously doubt any serious interest from those who pass by it because theyd have to sign up. I am not posting my art here just because I want to share it. I am not that altruistic. What I want is feedback and as I would not get any feedback from non-members anyway, I would see no reason to change the current system.