Step 1
The user registers on the site, then an email is sent to confirm the subscription.
Allow users to register on the site without intervention on your part.
Step 2
The user confirms the subscription.
Step 3
The user can access with their username and password and modify their data. Or unsubscribe from the site.
Step 4
The site administrator at all times has control of unsubscribing, registering, or modifying any user.