re: hey - how'd you do that?
If what you mean is cleaning off the board of old posts, he just entered a new thread. Ideally, a thread that goes unmodified for 24 hours (I think it's longer for some boards) goes "below the line," but there seems to be a minimum of one or two posts that have to stay above the line, even if they're old. Unless someone adds one or two new threads, these old posts stay above the line.