How does it work: Fully integrated with subscribe by email with Facebook and Google

Hi Team,

How does it work: "Fully integrated with subscribe by email with Facebook and Google"

- Should I establish a Setting for it?
Because I don't receive the e-mail when someone replies to my reply on a post... or when someone replies to the post...

- Can the user turn off the "subcribe by email"?

Thank you in advance.
Cheers, Stijn