I've seen several very informative and helpful posts from Nelson Pass (of Pass Labs fame) on (IIRC) A.Asylum. And then of course there were plenty of posts by Udo Zucker on the TAG forum...although I guess that may not now be considered an unequivocal plus.

However, while the enthusiastic posters probably spend a lot of money individually, it's probably not a high proportion of the total national/world HIFI spend, and certainly lower margin when viewed by manufacturers and dealers (as we'll go for a higher proportion of ex-dem/s-h deals). The only stuff I've bought new is the tweaks  , something I would never have contemplated before getting involved with these fora (although I would also have never contemplated more than £500 on a component).