Subscribers in the Admin section

I just discovered that I have a lot of “subscribers” while I was installing Jetpack today. The “subscriber” role is exceptionally obfuscated within WP, so I want to know what exactly they are subscribed to?

These folks are in the admin panel: Users>All Users. They are NOT in the Jetpack(JP)area. I like the WP subscriber email look/feel and want to use that. Will JP email my existing subscribers, of must I lose all of them because they are not actually subscribed to anything?

And WP, I know you are busy and this is “free” but the whole subscriber setup is insane. If my current subs are not receiving new post excerpts from me NOW, then WHAT IS THE POINT of having a subscriber area?

If they ARE receiving new post excerpts from me now, then WHY JETPACK SUBSCRIBERS?

This is a very important process and WP’s management of it is bad. Tighten it up, simplify it and make it work perfectly as expected with a single “Activate Subscriber list mailing’ (check for Yes)”