The defining feature of the Internet is universal resolvability -- having the
proper Web site appear in the proper place consistently and predictably, from
any place in the Internet.
To ensure universal resolvability, every Web site and other resource on the
Internet is assigned a unique numeric code (called an IP address) that allows
computers to locate it. Because the people who use computers prefer word-based
identifiers, numeric codes are tied to easy-to-use names, called domain names.
The Domain Name System (DNS) links the text names to the numeric IP addresses.
The Internet and the DNS are not owned by anyone, but systems are monitored and
maintained in a number of ways. For example:
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Internet
Corporation for Assigned Names and Numbers
(ICANN) is the nonprofit organization that manages and coordinates the DNS.
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The Internet
Engineering Task Force
(IETF) oversees the creation of standards that help define the Internet's basic
infrastructure and, by extension, the ways we use the Internet.
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Registries are organizations that operate top-level domains (TLDs), such as
.ORG, .COM and .NET.
Every TLD is managed by a registry. PIR manages .ORG and maintains a database
that contains the Internet whereabouts of every .ORG domain name. Every Web
site, for example, exists on a name server. When a user types a Web address,
such as www.example.org, the DNS starts a process of finding that domain's
location or name server.
How computers find Web sites 
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The user types www.example.org into an Internet browser window.
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The user's computer contacts the user's Internet Service Provider (ISP) to see
if www.example.org is recognized or stored in its cache (recently used files).
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If www.example.org is recognized by the ISP, the process jumps to step 7. If it
is not recognized by the ISP, the process continues with step 4.
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The ISP contacts a root Domain Name Server (DNS).
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The root DNS contacts the .ORG zone file server, which is managed by PIR.
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The .ORG zone file servers returns the IP address and name server of
www.example.org to the ISP.
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The ISP, which now recognizes the IP address and name server of
www.example.org, contacts www.example.org and asks for information for the
user.
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www.example.org returns the data to the ISP.
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The ISP sends the information for www.example.org to the user's computer, and
the browser presents the Web page.