I'm not arguing his case in particular, I'm trying to explain why you cannot simply allow the owner of a site immunity from what's on it. It's not a black and white situation, however what you're suggesting is simply too easy to exploit. In the UK the line has been drawn at the publisher being aware of the content and allowing it to exist.

If you think of someone posting something not as them modifying a site, but as them submitting content to the admin for approval, it can be deemed approved (and therefore publish by him, not them) if the admin has made it available to the public, and knows that he has.

So I would contend he posted all those links. The other users informed him of them by posting a notification on his site, he then saw them, and approved them for publication by not removing them.

And it's a really, really bad thing. People post millions of videos on youtube every week, it's not POSSIBLE to track them all.

Site admin is not obliged to monitor the website 24/7 for illegal content in Poland, thank god.

You're by your definitions just put every site owner on risk of being prosecuted, because on every forum, every blog, every website with comment section, there might be something illegal.

By the way, are you saying that if someone will offend the queenon your webiste, you, as the admin, will be guilty of offending the queen? Not the person who wrote this? It's just bullshit, man ;-)
What you say, means that people may post any shit they want, the person to blame will always be the admin.
edit: yeah, this is the last post :P