bumping
I think you're referring to the reply link that accompanies each post ? That was only intended to be used if you wanted to say you were replying to that particular post, generally if there's been other posts in between then and now, and you want to make sure everyone knows exactly what other post you're responding to.
The usual way to reply to a post is to hit the Post a Reply link on the right hand side of the menu bar at the bottom of the screen. :>