Website Usability Guidelines

Follow these strategies to improve your branding:

Allow the use of domain names with and without the www. Many Web users don't bother to type in the www and you'll lose credibility with those customers if your site doesn't work without the www. Use the full domain name with the www. On all publications it needs to identify the name as a Web site. Studies found that without including www on written documents, people were unsure whether the name referred to a Web site or an email address.
Support domain name or prefix typos, e.g., w, ww, or wwww instead of www.
Follow the Policy on Domain Registration, and use .gov, .fed.us, or .mil domains.
Reserve similar and abbreviated domain names, and redirect the traffic to your main site, e.g., polarusa.net and polarusa.us redirect to polarusa.com. Most domain names are relatively inexpensive to procure and reserving those that are similar to your domain name will help your customers find the right site the first time.
Before adopting a new domain name, check for synonym sites using the .com, .org, .net, .info, .biz, and .us suffixes. You may be able to buy those domain names; if not, at least you'll be aware if your competition is unsavory. This information may also convince your management to choose an alternative domain name.

Avoid extra punctuation in the domain name, such as hyphens, they're hard to remember.
Numbers may be used as part of the domain name as long as they are meaningful and memorable. There are drawbacks, numbers may be harder for customers to type and there could be confusion between some numbers and words (such as for, four, and 4).
Short domain names (12 characters or less) are best because people often type them manually.
Avoid using mixed case since people can't remember the difference between upper-case and lower-case characters; and domain names themselves are case insensitive.
When creating a new domain name, consult your Web logs to see what keywords customers are typing to get to your Web site, perhaps those keywords should be part of the domain name.
Avoid unmemorable and unintentional acronyms; both can damage your organization's reputation.