Hi there!
It’s worth noting that Registered Users and Jetpack subscribers are two different types of users:
– Registered Users appear under Users > All Users in your dashboard, and register through the “Register” link on your log in page:
https://hatemeorlove.me/wp-login.php?action=register
You receive an email notification when they do so. They do not receive any notifications about your new posts, and are not related to Jetpack in any way. You can disable these registrations by going to Settings > General in your dashboard.
– Jetpack Subscribers can be found by following these steps:
https://jetpack.com/support/subscriptions/#view-your-email-subscribers
They do not appear under Users > All Users, and you do not receive an email notification when they sign up. They can sign up via the Subscription form in your sidebar.
I hope this clarifies things a bit. Let me know if you have any questions!