Clarification - we're not archive.org. Archive Team and Internet Archive are completely separate.

And we're only archiving things that "any guy on the internet" can see. If someone can access the messages simply by joining a group (with no moderator approval), I'd argue it's fair game.

We're not going to be unreasonable, though. If something private slips through and we receive a takedown request from the author, we typically remove it.