So here's what I've seen on various other forums. It's a bump button. It bumps the thread to the top without the user having to post. And can only be used once every 24-36 hours. Pretty awesome idea, amirite?
This feature is already here. Subscribe topic | Bookmark topic | Print view | E-mail friend In there, you'll see | Bump Topic
Well, how many is x? I can't recall seeing it on any of my 6-7 day old topics... Edit: Oh, I found it. I'm still curious as to the number of days it takes to make the button appear...