Besides the usual "ask a lawyer" (which I plan to do, but am trying to get some background information and possible case studies first) responses, I wonder about the liability of the site owner if users violate local (or national) laws by their actions.
Let's say a site allows people to create groups (similar to Meetup) and the group owner can make the group public (anyone can join) or private (group owner manually approves each member). One group owner decides to create a group and refuses to admit anyone from a certain protected class of people (e.g., a certain race). In the U.S., this type of discrimination would be illegal. So what would be the site owner's level of liability for this?
My understanding of Safe Harbor is that it can provide some site owners with certain shields against liability for copyright issues in some cases, but it seems to be vague in terms of other legal issues.
Has anyone ever had (or come across) a situation like this?