This is where domain names enter the picture. A domain name can be thought of as a mnemonic, an aide-memoire to help people find your site. It is an alias for the IP address 207.113.171.151. It is possible to set up many subsets of a single main domain name. Each subset could be connected to a different web site.
Domain names are now a common sight in newspapers, magazines and other media.
If you are walking past a billboard or reading a large ad, take a look down at the bottom of the advertisement. Another significant feature of domain names is that they are unique. This is what has precipitated interest in domain names, and what has lead some companies and individuals to pay a great deal of money for a name. This can be done by deleting the association between the domain name and the old IP address, and associating the name with the new address. This process can be carried out very quickly, and will be entirely transparent to visitors to the site, who will continue to access it via its domain name.