Domain names lend simplicity to their corresponding numeric Internet Protocol, or IP address, so that Internet users can easily search for the site that they want. Instead of searching for 207.151.153.3, which is tough to remember, users simply type www.internic.net, which is easier to remember. There are currently millions of domain names registered worldwide throughout various registration companies. ICANN, the Internet Corporation for Assigned Names and Numbers, manages and coordinates the entire Domain Name System (DNS).
The Domain Name System
Domains uniquely identify network computer addresses. The DNS hierarchy consists of host names and domain levels from top level to root separated by periods. Each label between each period is a level of that hierarchy. The root level begins at the far left and the top level domain at the far right. Look at the example www.computer. biographyeditor.com. The "www" is the host name label. The second label, "computer," is the subdomain. "Biographyeditor" is the second-level domain label. "Com" is the top-level domain. Remember that the syntax reads left to right, lowest to highest level domain.
Registering a Domain Name
Every country has its own domain registration companies. These competing companies, called registrars, submit your contact and technical information to a central registry providing Internet users with a way to contact your website or e-mail. Your public information is noted on your site's "Whois" page. There are contractual terms that you will need to sign with your chosen registrar under their specific registration criteria, including registering under a third party name. Registrations are renewable up to 10 years, often in annual increments, depending on registrar policy.
Whois
Whois, a domain research service, enables an Internet user to search for a specific domain name, see if it is registered, what data is registered, and find available domains--new and previously registered--for purchase. If you use the previous example (www.computer.biographyeditor.com) and search Whois.net, you would find that it is an available domain. If you searched for www.merldworld.com, you would find that it is not available and would see its registration data.
InterNIC
InterNIC gives Internet users information regarding domain name registration services. You can file a complaint or initiate a dispute as well as search for accredited ICANN registrars and report inaccurate Whois data. InterNIC is an ICANN site.
ICANN
ICANN, the international non-profit, makes sure that every numeric IP address has a textual domain name uniquely mapped to that address. Acting as an overseer, it performs the original U.S. government services of ensuring the "operational stability and integrity" of the Internet. Simply put, ICANN makes certain that Internet users can easily access the sites that they wish to access.
Quantity of Registrations
ICANN keeps track of registered domain names and how many there are on any given day. This number changes daily. You can find the number of IPs by country on Whois, which lists over three billion IP addresses in 240 countries. This translates into over three billion domain names, of which nearly 88 million are actively registered.