What makes a valid domain name?
Letters and numbers are always valid characters. Hyphens may also be used in but may not begin nor end your domain name. Spaces and special characters are never permitted. The special characters include, but are not limited to, these special characters: ! @ # $ % ^ & * ( ) ? "
You can use up to 67 characters in your domain name, including the extension .com, .net, .info or .org. "www." and "http://www." are not considered part of your domain name and do not count towards the 67 character total.