Thanks to everyone for the great -- and passionate -- feedback, both about using a blog for discussion and the permissions proposal. The most important realization is that trying to follow threads both on the blog and in the forums is wasting everyone's time, so permissions (and future design discussions) will move back into the forums where they belong. I'm going to continue using the blog (http://secondlife.blogs.com/prompt) to experiement with .plan style data, but the next version of the permissions design will go into the forums, probably on Wednesday.
Along with that, I've removed the permissions thread from the blog. The forum thread on permissions is better read, has all the critical pieces cross posted, and has far more useful comments. In addition, so many good points have been made about flaws in the design that it's a little silly to leave it up on the blog. Instead, look for a much improved design that incorporates your many, valid concerns in a few days.
OK, off to test attachment bug fixes.