I just have one quick thing to add to this discussion. I do agree that 100 plus posts and 2-3 month membership on the boards should be required for membership in the ToE.
As for sponsorship - there are strong opinions on that, the whole invite thing - so obviously that's not going to work.
What could happen is, when a person wants to gain access to the ToE, they have to let the admins know two weeks before their 3 month / 100 post mark. They would then be given Read Only access to the forum for two weeks. That way, they wouldn't be jumping in headfirst (so to speak ) They would have a chance to read through the threads, and understand the atmosphere and "unspoken rules" before they started posting.