Outside of Wikipedia, I'm not sure what content you are thinking of.
Taking HN as a potential one of these places, it doesn't even qualify. HN is funded entirely to be a place for advertising ycombinator companies to a large crowd of developers. HN is literally a developer honey pot that they get exclusive ad rights to.
But what is your point? Is the value in HN primarily in its hosting, or the non-ad-supported community?