Usenet - misc.fitness.weights
Okay, not a "web forum", but an established on-line community, and definitely a body-building forum (tho mostly given to powerlifters & flame-warriors these days); started reading it more than 10 years ago & posting nearly 10 years ago.
MFW alumni include Patrick Arnold, Bruce Kneller, Dan Duchaine, Bill Roberts, Lyle McDonald & Elzi Volk (I first ran into Lyle & Elzi (and Dan) on the
lowcarb-l mailing list before they moved to MFW) - and, of course, the famous Mistress Krista.
Trygve Lode runs the
MFW webpage, in case anyone cares.
An mfw post lead me to Bulk Nutrition as a possible alternative for Beyond-A-Century; skimming the forum there, I found links to Avant Labs & AnabolicMinds, and I've been here ever since (with forays to Avant from time to time).