To further add to what Joe said, there is a rule for this forum. It states "7. Any member who shows no forum activity within twelve months (12) will be removed from the membership roll." Sounds ominous, but all you have to do is login in order for your "Last Online" date to be updated. Don't even have to post, just login once a year.
Of course, it would be nice if everyone participated, otherwise why join a forum?
I often wonder why someone would join and then just vanish. But unlike other forums, we do housecleaning to remove these folks as it serves no purpose to retain their membership record. We don't have to impress advertisers with numbers that include folks who do not participate in our hobby anymore for a variety of reasons.
I have to laugh when I see other forum numbers that are touted. Reminds me of this.