What is a URL?
Since websites are considered resources, and every website the world over has a unique address per a uniform addressing scheme, “Uniform Resource Locator” (formerly Universal Resource Locator) or URL, is a fancy name for website address. A synonym that is actually more precise but less well-known is URI, or Uniform Resource Identifier. The term “URI” developed after URL had already gained widespread public use; hence URI is used by those involved in Internet development, standards and protocols, while URL is the prevalent term outside those circles.
A Web browser is software used to cruise the World Wide Web. Every browser has a URL window where the address of the currently viewed webpage is displayed. Clicking on a hyperlink within a webpage will direct the browser to a new URL or Web address, changing the text inside the URL window. In tabbed browsing the active tab’s address will show in the browser’s URL window. A website address can also be manually typed or pasted into the URL field.
A URL can be composed of words, such as “wisegeek.com,” or the corresponding Internet Protocol (IP) address: 69.93.118.236. Either address will take the surfer to the wiseGEEK site. The vast majority of surfing is done by entering the name of the website, as names are easier to remember than numbers. Most people never even know the IP addresses of the websites they visit, but every name maps back to a unique, numerical address.
It’s a good idea to be at least marginally familiar with what a website address looks like. Common webpages start with http:// for HyperText Transfer Protocol. Pages that start with http:// are not encrypted, so all information that passes between your computer and the Internet can be “seen” by eavesdroppers. For this reason it is unwise to enter personal information into a webpage that starts with http:// in the URL window.
If you are about to enter personal information into a webpage, first check that the URL starts with https://. The extra “s” stands for “secure” and indicates the information exchanged between your computer and the Internet will be encrypted, making it useless to eavesdroppers or hackers. If a part or all of the transmission is captured en route, it will only appear as blocks of garbled characters.
When downloading or uploading files to a website, the File Transfer Protocol (FTP) is often used. In this case the URL address will start with ftp://, with the website address following. Often people use special FTP clients (software) to more easily handle transfer of large files, rather than using a Web browser. FTP clients are especially useful for domain maintenance, and are more streamlined than a Web browser.
Source: WiseGeek