1.3 It’s All about Being Connected!

In its simplest form, the Internet is a collection of connected documents or objects. Hyperlinks are what connect these documents.

A hyperlink is a virtual link from one document on the World Wide Web to another. It includes the uniform resource locator (URL)The unique identifying address of any particular page on the Web. It contains all the information required to locate a resource, including its protocol (usually hypertext transfer protocol [HTTP]), server domain name (or IP address), file path (directory and name), and format (usually hypertext markup language [HTML] or common gateway interface [CGI]). of the linked-to document, which describes where on the Internet a document is. It is what you enter in the address bar of the browser because it is the address of that document on the Internet.

A URL provides information to both browsers and people. URLs include domain names, which translate to Internet protocol (IP) addresses. Every Web site corresponds to an Internet protocol (IP) addressUsed to uniquely identify a computer and system on the Internet., which is a structured series of dots and numbers indicating where it is physically located. When you enter a URL into the address bar of a browser, the DNS record indicates where the document is that you are linking to. Many domains can translate to the same IP address.

Confused? Look at the domain name and IP address for Quirk’s Web site:

• Domain name. http://www.quirk.biz
• IP address. 212.100.243.204

A domain name looks something like this:

http://www.domainname.com

But a lot more information can be included in this. Domain names can carry the following information:

subdomain.domain.tld/directory

• DomainThe unique name that identifies an Internet site. Every domain name consists of one top- or high-level and one or more lower-level designators. TLDs are either generic or geographic. Generic TLDs include .com (commercial), .net (network), .edu (educational), .org (organizational, public, or noncommercial), .gov (governmental), .mil (military), .biz (business), .info (informational), .name (personal), .pro (professional), .aero (air transport and civil aviation), .coop (business cooperatives such as credit unions), and .museum (museum Web sites). Geographic domains designate countries of origin, such as .us (United States), .fr (France), .uk (United Kingdom), and so on.. The registered domain name of the Web site.
• SubdomainA domain that is part of a larger domain.. A domain that is part of a larger domain.
• TLDThe top-level domain, uppermost in the hierarchy of domain names.. The top-level domain, uppermost in the hierarchy of domain names, also known as the domain extension.
• DirectoryA folder to organize content.. A folder to organize content.

The TLD can indicate the country in which a domain is registered and can also give information about the nature of the domain:

• .com. The most common TLD.
• .co.za, .co.uk, .com.au. These TLDs give country information.
• .org. Used by nonprofit organizations.
• .gov. Used by governments.
• .ac, .edu. Used by academic institutions.

Domain names must be registered, and there is a fee for doing so.