Your email address is required to ensure that there are no duplicate entries. Also, if you indicate that you are interested in being a beta tester (the last question), then your email will be used to contact you. Otherwise, your email will go nowhere and will not be put on any mailing list of any kind. I respect your privacy and value your feedback.
Finally, besides your email, no responses are required. It is important to me that you to have full choice about what you share and I am thankful for any and all information provided.