Note that if you post to the newsgroups, it is public information. The news server does not require you to log in and won't work if you try to log in. I post replies, but my friends don't see them. My friends on other servers see different messages. Welp, news is a funny thing.
Different providers have different news feeds so different messages can end up on different servers.
Newsgroups are not like a TV broadcast where everyone gets the same thing all the time. Also, different ISPs devote varying amounts of resources to news.