A more important matter is the way the group should be implemented. Moderated or unmoderated doesn`t matter, as the server already knows how to send messages to moderated groups to the moderator.
Actually, I was thinking that whistleblower@anon.penet.fi would _be_ the moderator. Then you just post directly. All the messages would come from that address, and no id's would be assigned. Since all messages are from "whistleblower", replies to a poster go right back out to the list, also anonymized. It's actually a much simpler system than is currently implemented, since id's arenit involved at all.
Pros are that it would make it very hard to track down the real poster, cons that it would be impossible to tell the different posters from each other, thus not enabling informers to earn good or bad reputations, unless they include key signatures or something.
PGP 2.1 contains the cleartext-signature feature, and the periodic posting to the list should mention this. This allows a real pseudonym to develop, just like we want. Eric