Okay, two things here (third doesn't count), both are likely to be shot down by others, but I like the ideas:
One)
What: A Private board. That is to say, a board where any thread you start can only be read by you.
The Purpose: A place to put character sheets and monsters you don't want everyone else to see. Or anything else you don't want others to see.
The Reason: I think this would go quite well with how many people here are PbP DM's / players.
My True (personal) Reasoning: There are times I want to keep the Meta about my character in RL games a secret, meanwhile I'm constantly directing my group-mates here, most of them know me by my avatar too. So if they come here and I've got a sheet up, bam, they know my Metagame; I am tired of using my signature thread as a workground for projects that aren't ready for their own thread yet. See the heavily WIP class / discipline combo in there now. But it is a place I am reasonably sure that no one else will notice until I'm ready to move it elsewhere, a Private board will alleviate that; I will soon be an active PbP DM, and I would rather have things here, formated in ways I can do here, than on my Laptop, formatted in Word.
Two)
Putting my vote in for a Sig board.
I disagree that that would be "putting our indexes in an Index". It would be putting our index files into a folder.
@ Osle: Your sig has a link to your Monster Classes. As does, well, everyone else's. In your monster classes board, you have an index. Your index (Sig thread), leads to a folder (board), that contains its own index to locate content within that folder (board). You do not have an "index in your index". You have a very efficient system of indexes and folders.
That said... as idiotic as this might sound at first, bear with me
Three)
Mayhaps someone should make an Index.. of our indexes. The Hanbook Index, the Homebrew Indexes et cetra. Name should probably be something along the lines of "Your first stop for info, even before you search"
.... That sounded smarter in my head, and it didn't sound smart. But hey, it is some kind of thought.