The lfs-announce list is a moderated list. It can be subscribed to, but you can't post any messages to this list. This list is used to announce new stable releases. The lfs-dev list will carry information about development releases as well. If a user is already on the lfs-dev list, there's little use subscribing to this list as well because everything that is posted to the lfs-announce list will be posted to the lfs-dev list as well.