Domain names are not case-sensitive, which means they make no distinction between small and capital letters. Even though Internet addresses (domain names, web addresses, mail addresses...) are generally written with small letters, you are free to mix capital and small letters when you mention your domain on your letterhead or in your campaigns (WhoIsComing.b, for instance). Be careful though: this only applies to domains: for paths to HTML files, you have to use the exact spelling. Example: www.mydomain.be points to the same address as www.MyDomain.be. But those who enter www.mydomain.be/specificfile.htm instead of www.mydomain.be/SpecificFile.htm will get an error message.