Well the net is a very mobile place with lot's of places to visit. Some posters will run across BFF while looking for something in a search engine, post some comments, then move on elsewhere. There are many forums that I visit occasionally, put months may go by that I don't post anything at them.
I think one I really wonder about is "JB". He was definitely a regular here, posting nearly everyday, then one day he just disappeared. I really have a feeling something happen to him.