Interesting thread.
PPRuNE is the only aviation internet forum I visit, that said these days I don't visit it so much.
Sometimes there are genuinely good threads that appear with many useful nuggets of information and (sometimes heated) discussion, but recently that seems to have tailed off somewhat. Most of the threads posted here of late I don't find much use, but that's me personally. Others will still find this a goldmine, depending on what's relevant to you.
Also, like all internet forums, there is a hard core element of trolling activity, know-alls and childish arguing that I can't really be bothered with. Opinions are cheap and plentiful but rarely any use.
Still visit at least once a week, but hasn't been much happening of late.
Smithy