If you send a message to: PAF5-USERSemail@example.com you will be sent a message in return asking you to confirm that you wish to subscribe, by replying to that message. When you do that you are a member of the PAF5-Users Group. There are no questions asked, no forms to fill in. You can post messages simply by replying to the messages sent or by sending your own message to PAF5-USERS@yahoogroups.com However, if you wish to join Yahoo!Groups, then you are asked to fill in some simple questions. Once you have done that, then you can access the home page of any Yahoo! Group and become a member of any of the Groups on-line. That includes the PAF5-USERS Groups at http://groups.yahoo.com/group/PAF5-USERShttp://groups.yahoo.com/group/PAF5-USERS.
If all you want to do is read and post messages there is no form filling nor questions asked - just like this list (well they do ask a couple) or any other. That's how it worked for me today when I subscribed.