The internet existed before ads, too. This website we're on now has no ads.
Advertising is not the inevitable endgame of any particular forum. It's only there because we accept it. If I go to my public library and ask if I can put up a flier, they say "Are you a local non-profit? Then you can post it on the bulletin board in the back corner." Just because they can run ads doesn't mean they must.
It'd be great if the people who want an ad-laden web could have their side, and the people who want a free volunteer web could have their side. There was a time when I might have thought that .com/.org could do this, but clearly that distinction is long gone.