Probably because you would need to remember what the addresses were, what your credentials were (for each forum you joined) in order to participate. Also, admin

Probably because you would need to remember what the addresses were, what your credentials were (for each forum you joined) in order to participate. Also, administrators could disrupt discussions any time they wanted or restrict people from posting in the same vein. Usenet, on the other hand, didn't have these problems, though it pretty much ended up the same way.