I'd like to suggest allowing users to create their own custom posting headers, similar to the old Usenet X- headers.
For example:
X-Coffee: Black X-Mood: Grumpy X-Currently-Reading: Dune X-Listening-To: Johnny Cash X-Favorite-OS: Whatever gets the job done
They'd simply appear with the normal posting headers for anyone who has headers enabled, while users who hide posting headers wouldn't see them.
It would be a fun way to add a little personality to posts while keeping with the classic Usenet feel. Since they're just informational, clients that don't care about them can simply ignore them.
Maybe at most, 5 extra headers max.
Tom Mix
"Leave the trail better than you found it."