Hello
Have you ever logged onto the IRC channels? Their seems to be a healthy community built up around them.
Have You ever been on a chann witch 1000+ users? Believe me, that's not a healthy community - it's noizzzzze:
-- user x joined -- user y parted
(loop indefinetly)
But i've been on forums with 2k+ users, and they're still readable.
Still - i'm not advocating for a forum - a mailing-list is still perfeclty readable as far as i'm concerned. Tho i do know, that many younger people have no clue about mailing lists, or how to even subscribe, on the contrary they can point a browser and easily register/log in on a forum.