By law, every domain name must contain valid whois, or contact, information.  A person can do a search for any domain name and find this information, including your email address.  Spammers will typically scour new domains using a whois search engine, such as http://www.whois.sc/, for this information.  Below is an example of what an unprotected domain name looks like vs. a protected domain:

Unprotected

Mynewdomain.com
Administrative Contact:
Administrator, Domain jdoe12345@aol.com
John Doe
123 Candy Cane Lane
Seattle, WA 98005
US
+1.5551235467

Protected

Mynewdomain.com
Administrative Contact:
Administrator, Domain enom@pagedepot.com
iHost Networks
P.O. Box 357
Preston, WA 98050
US
+1.4256440288

It is recommended that you use a Privacy Protection for your domain name which will mask the contact information.  This service is available, and it costs $15.00/year which must be renewed yearly.  If you are interested, please contact our sales department at the phone number at the top of the page, or submit a ticket from our ticket system..

Note: Currently, only .com, .net, .org, .info and .biz can have privacy protection enabled.