Without a clear address, no message reaches the recipient on the Internet; in this respect, 'virtual life' and 'real life' are similar. This address, called a 'domain', is a coherent sub-area within the Internet hierarchy that allows exact addressing. Network customers can freely choose the names of the domains - if not already assigned. They register the name with the responsible registry, the NIC (Network Information Center) of the respective top-level domain to which the endings on the far right of the Internet address refer (e.g. .de, .com or .org). In Germany, 'DENIC eG' registers all Internet addresses ending in .de.

The domain system resembles a widely ramified root system. At the top of the hierarchy is the root level, followed by the top-level domains and then the subordinate second- and third-level domains. In the address www.brm.de, for example, the 'www' is the root level that refers to the 'World Wide Web', the '.de' determines the German top-level domain, a 'brm' refers to our own domain in the second level, and possible further additions in the third and fourth levels allow precisely defined pages on our homepage to be accessed. The selection and registration of domains is a standard task, also for our for our IT service.