It would be neat if each individual post had UNIX-like permissions so that you could grant or take away moderation abilities (i.e. edit/delete) for an individual post for usergroups lower in the hierarchy than you. To best illustrate this, here are two use cases where this would be useful:
1) Post locking (not to be confused with thread locking): When a moderator needs to remove something from a post and wants to make sure that the user cannot re-add it, it would be useful for a moderator to remove the edit permission for that post from the posting user. If this action was done by someone high up, they may not want lower mods to overrule them, so it would also be useful to remove the edit permission from lower-level moderators.
2) Wiki posts: Many forums have the concept of a wiki post where any user can modify the post. Wouldn't it be neat if
every post was just a subcase of that? Below the Original Poster permissions group, there could be an All Users group that can be granted the edit permission.
Although I envision there being an advanced permissions editing menu, I would expect these common actions to be a simple alias to those permission settings.
While we're talking post permissions, I might as well add that a separate "read" permission would also come in handy. Use cases:
1) Moderators can leave hidden posts saying things like "I cleaned up this thread up to here, and this is what I did". (Hidden-from-the-user mod notes for individual posts would be nice too, but that's a separate feature)
2) Users could make
custom usergroups and make it so only people in that group and above (OP, mods, admins) can read the post. Think of it like Kickstarter's backer-only updates.
