Its pretty easy to subscribe to the forum.
1- You must be a registered user on the AAVSO site. You don't have to be a member, but you have to be registered.
2- Near the bottom of the pages with messages in the forum is a link from the word "subscribe". Click on it.
3- Three choices will appear:
- Subscribe to this page- only notifications from replies to this page will be sent.
- To Forum topic content- notification of any post or reply to any forum--everything! Aaagh!
- To content in Cataclysmic Variables- any posts or replies sent to the CV Forum only. (Check this one)