How exactly does the email notifications and subscription settings work?

Here are my assumptions on how it works, though I am not 100% sure about the details:

1. The users can go to http://<osqa domain>/users/<user id>/<username>/subscriptions/ from the User tools and simply check the radio buttons or checkboxes for the notifications that they would like to receive.

2. The user needs to have the Email field in the profile page with an email address.

3. The email needs to be validated first in order to receive emails.

4. The users receive notifications right away whenever there is an update to the particular items selected from the settings.

5. When the daily digest checkbox is checked, the users will no longer receive individual emails, but will receive just one email containing all the updates selected in the settings.

6. The stop notifications button will uncheck all checkboxes and select all No Notifications radio buttongs, practically disabling all email notifications for that user.

Are all of these items correct? What else did I miss about the email notifications and subscriptions functionality?