Are users or is the site owner responsible for posts on the forum?
Could it be different:
- with or without a license agreement available on the site?
- with or without a registration?
My concern is about Russian law primarily.
When users sign up for forums they agree to the site's terms. Those usually include parts about not posting content that goes against the rules or laws. If the user goes against the terms, then they're the one who's responsible; if the forum owner is promoting things that are illegal, then they're the one who's responsible. For example, if they started a thread linking to pirated content and others comment on it, it's still the owner's responsibility for having posted it in the first place even if they didn't know it was pirated at the time. The site owner could change the terms at any time, but changing the terms won't change who was responsible for going against the country's laws.
In short, if a user posts something against Russian law, it's usually the user who's responsible and if the forum owner wants to moderate those sorts of things it's entirely optional. Think of it as a "luxury." Take YouTube for example: there's sometimes content that goes against piracy laws, but it's the uploader who's responsible and YouTube chooses to remove this content to get a good reputation.
Further, even if the site has no terms when signing up, the users are still responsible for their own breaking of various laws.
So the takeaway seems to be that if online forums are maintaining the necessary paperwork, have their servers in the right place, and provide the authorities full access to their code and userbase, the authorities just go after the users they're interested in... presumably so long as the forum operators are not seen as activists or 'persons of interest' themselves.
Like with China, this is probably one of those areas where there's a fairly wide gap between the laws as written and as they're actually enforced, which has the "benefit" of making the ISPs fall over themselves to establish whose side they're on and establishing grounds for banning American services, which Putin thinks are working with US intelligence services.