It's simple. I ask for your name and email on the sign up form so I can send you newsletters hosted by Mailchimp, and so in the newsletters, you can receive the password to put in the URLs like GIFT FOR SUBSCRIBERS to receive your gifts. That's it.
The publisher, Insubordinate Books, uses your email to send you sporadic newsletters. Each newsletter has its own Unsubscribe opt out which is simple. However, if you have any problem.