For me it depends on the question. The funny thing is that answers existed and have been available by doing a search before serverfault and friends existed on the web :)

As a "community"....none. We are large group of people gathering in the same virtual space. We have no responsibility "as a group". Each is responsible for their own actions etc. (At least that's what I think my lawyer would like me to say) - Before we have someone suing "the users of an online community" wholesale as a group.

Yes. But when you know the answer it's hard not to blurt it out. That's why someone once said "with knowledge comes responsibility" - [ and if someone knows who that was, add it as a comment]