Not sure about HN but there's plenty of evidence of intelligence agencies using Reddit to craft public opinion.

Look at the demonization of the US's geopolitical rivals and the stories that get pushed. For example, questioning the Russian bounties story for a while would get you responses of "Russian bot". We know now the Russian bounties story was weak from the start: https://www.nbcnews.com/politics/national-security/remember-...

Repeat ad nauseam for other geopolitical rivals.

I don't see them interested in nerds and in nerd-culture, to be honest, eventually maybe there are some FBI or Secret Service lurkers in here, definitely some past or present NSA employees/collaborators.

Maybe they've been too busy over at Wikipedia to have time for HN?