My users are completely confused about the difference, that's for sure!
?If their prior experience is Yahoo Groups then they're probably over-thinking it. In Groups.io obtaining web access is only a few clicks away - not the confusing song-and-dance Yahoo puts one through.
At the logon screen click "Email me a link to log in"?.
Enter your email address, click Send.
?Click on the link in the email message that arrives ?(watch for it in your Inbox and/or Spam folder).
Now the user is logged in and can navigate the site as a member of whatever groups their email address is subscribed to.
?
There is no actual need to set a password or "establish an online profile" or go through other formalities. They can, but those are purely optional. All they need to do is log in.