I've just been trying to find a list of WMD editor keyboard shortcuts - and I can't see one. There's the formatting reference, but I can't see a keyboard shortcut list. Obviously this could be addressed as a FAQ entry, but there's a better way.
Google Reader has a very nice feature whereby if you hit "?" while you're not editing anything else, an overlay pops up with all the keyboard shortcuts. Obviously we couldn't use "?" in quite the same way, but even just a little "keyboard" button next to the help button at the top right of the edit box would be a reasonable trigger.
This would be particularly useful for any shortcuts which don't map directly to buttons. There may not be many (or even any) now, but I can imagine some possibilities, particularly if other feature requests are accepted.