You can think of your Web site's domain name as the persona of your online enterprise. Since your customers will equate your domain name with your business for years to come, picking the right domain
Your domain name should reflect be your company’s name, describe the services you provide, or describe what you sell. Keep your domain name as brief as possible, to make it easy for your customers to remember.
A domain name must be at least two characters long, and can't contain illegal symbols, such as $ # or @. Underscores and dashes, however, are acceptable.
Top level domains, or TLDs, are the letters after the "dot" in a Web address. There are several different types of generic TLDs, including .com, .net, .org, .info, .biz, and many others. The first three are by far the most popular, and you should attempt to register your name with one of these three extensions.
Whenever possible, register a domain with the .com extension. Most users automatically associate a domain name with .com. If you are using mybusinessname.info, and another company has mybusinessname.com, you will most likely lose customers to them. Adult sites frequently use domains that coincide with the .com versions of popular domains, in the hopes of getting more traffic to their site. This is the last thing most small business owners need.