A domain name is your address on the web it acts as your URL (Universal Resource locater). It’s the information that customers type in to their web browsers (Internet Explorer, Netscape, Safari, FireFox, etc..) to find your website. It’s what comes after the www. in your www.domain.com. Like dsknights.com.
A domain name can be any combination of letters and/or numbers up to 63 characters. The official domain name extensions to date are .com, .net, .org, .biz, .info, .us, .tv, .tk and .ws. They are always adding more extensions, but you may want to stick with the ones that are most common for your particular target audience.
If you are planning on having a professional business (and we recommend you do) like [email protected] you will need your domain name for this as well.