Originally, anyone was supposed to be able to sign up for the Forum. The idea was to show the old car community how helpful this could be in hopes that they might join the club. Some people did join the club, most did not. The majority of forum members these days have been forum members for years (as in at least 2) and apparently have no intention of joining.
The original plan was to allow anyone to be active on the Forum for 6 months; if they did not join after that, their membership on the Forum would be terminated. Such things are often referred to in government as "sunset clauses" where something expires after a period of time.
I, and others would like to see the sunset clause on Forum membership be re-instated.