In the simplest of explanations, your domain name is your website address name. For example, DeMicco.com is the domain name for my blog.
A domain name is generally selected because it represents a business name, brand, product, or service. There is search engine optimization value in selecting a domain name that contains the principle keywords that represent exactly what it is you offer.
For example, one of our clients is Bendheim Corporation. They sell different types of specialty glass. They have a different website with a unique domain name for each of their product divisions, among which are www.architecuralglass.com and www.bendheimcabinetglass.com.
As part of a comprehensive search engine optimization campaign, selecting a domain name that contains your principle keywords is generally a good idea; however, if including your keyword phrase results in a ridiculously long domain name you may wish to use it as a landing page only or implement a 301 re-direct (see 301 Re-Direct for more information).
