We have over 1000 members, of which slightly over 100 are registered on this forum. Hoping to increase forum membership and to increase interest in the old newsletters, I ran an article in the latest (May/June) newsletter mentioning the forum and the availability thereon of back issues of the newsletter. In the month or so since that newsletter "hit the streets," there have been only four or five new forum registrants, and I don't know if any of them are members.
In short, roughly 90% of our members are not forum participants, and evidently unlikely to become so.
-John