Technical climbs may occur in the mountains, but gym climbing topics are also welcome. There is no charge to subscribe, and you don't have to be a member of any organization to send broadcasts or just listen in. All messages are archived, and are considered public domain. They may be included in various newsletters or forwarded to other lists.
Org lists are for gear discussions, political debates, etc.
Most broadcasts will be to announce future trips, report on past trips, or discuss road and route conditions. Keep in mind that any message you try to send out to the group should come back to you within a few hours to a day. You should get 2 messages when you subscribe. One is this file, the other is climber.org-rules.txt, and both of them contain stuff you'll want to know later. Even if you don't think so now.