This is not an issue at this point because there are not to many people YET. I just found your site and by the looks of it you guys will probably be adding many more members in the future. So, my suggestion would be to break up classifieds into sub-forums. Example, I want to sell a range finder. There is an OPTICS sub-forum where I would place such ad. this will allow users to browse certain areas of interest and also keep ads on the front page longer. Like I said, not a issue now but just a idea as your site grows.