[antimony]

Not exactly. By replying to a thread in any way it brings it to the top of the list. When you are looking at the list of threads in the a forum, you are looking at them in order where the one with the most recent reply is on top.

So if a sale thread has slipped down off of the first couple of pages, the original poster might reply to it to get it back on the first page. Since they have to say something in the reply, the most common thing to say is just "bump" - it's not a bhuz-specific term, it's what is used on other internet forums as well.