It'd be great to have a place where the differences between the permission levels are explained. While "Admin" vs. "Read-only" are pretty clear, the lines get murkier for what a "pro-user" vs. "user" vs. "guest" can do.

If this is posted somewhere already, I wasn't able to find it -- so if that's the case, maybe we just need additional ways to get to it (or preferably, a direct link from anywhere that permission levels can be assigned).