It is too easy to get free two way anonymization for me to feel these are necessary. The archive is free and not always available, but I do my best. I saw some spam in assm. Your newsserver may be misconfigured and accepting posts that should have been mailed to me for approval. You are welcome to try to use this technology for other purposes, but be warned that jmdigest is slow.
Simple story is there are at least tens of thousands of usenet news servers around the world.
Normally when you post it appears first on your local server, and then it distributes it to its neighbors and they continue the distribution. The result is that you can post and see something immediately, but it might not be seen by others for hours or days. With a moderated group everything happens at the newsserver the moderator uses, not your local server. This delay is quite noticible. Let's say an article is trying to go from X Industries' anvil newsserver to Waterbuffalo Breeding Inc's bnafh news-server.