A domain or domain name is what comes between the @ in your email address and the .com, .org, .net, etc. (For example, yourname@domain.com.) Domains help your customers find and remember where your business is located on the internet. A subdomain is a portion of your domain—sales.domain.com or marketing.domain.com—that can be used to help increase deliverability of your email marketing.

Building a Highly-targeted Opt in List: When Money Lies Beneath the Lists
Are you successful with your Internet business? Better yet, do you think you are successful with your online business? When most online entrepreneurs are asked with these questions, they often brush it off.