Many people believe that if they register a particular domain, for example www.arkansascoffee.com, then the person has trademarked that as a business name an no one else can use the name Arkansas Coffee for their business. This is not necessarily true. You must not only register the domain, but use the business name enough to achieve distinction, such as through customer awareness and marketing.
However, if a domain name is registered under bad faith, i.e. someone has register the domain name with the intent of selling it to the company with the same name, the domain name will not be protected under the Trademark Law. People who register domain names in bad faith are known as cybersquatters.