Being familiar with top-level domains (TLDs) will help you and your patrons understand the purpose of a Web site. According to the definition in Webopedia (www.webopedia.com), top-level domain refers to the suffix attached to the URL or site address. There are a limited number of predefined suffixes, and each one represents a top-level domain.
The most common top-level domains are:
– commercial sites are created to sell a product or service either online, as Amazon.com does, or more indirectly, by describing a product and its benefit to you. Often the reputable Web site owner posts valuable information on the Web as a part of the sales effort (for example, the text of a highly regarded medical source, The Merck Manual of Medical Information (www.merck.com/mmhe/index.html). The information on a .com site may be excellent or it may be false, depending on the integrity and desire for accuracy of the site owner.
– sites with this suffix are products of government. Originally used by the federal government almost exclusively, many states are now using .gov. Examples are www.whitehouse.gov (the Office of the President), www.census.gov (Census Bureau), and www.idaho.gov (the official Web site for the State of Idaho).
– U.S. colleges and universities have Web site addresses ending in “.edu”. In addition to admissions information, most institutions include the school’s library catalog, and information and databases developed by various academic departments. Academic Web sites frequently support faculty and student pages, often indicated by a “~” [tilde]; view these pages with a critical eye because they may support the author’s bias or, in the case of some students, may be designed to mislead you intentionally. For example, the Idaho State University Web site is www.isu.edu/. Faculty home pages may be designated by www.isu.edu/~[name of individual].
– designates largely not-for-profit organizations, all of which exist for a purpose. Regardless of your viewpoint, you will find some .org sites beneficial, some offensive, and some value-neutral. Do not assume that the creators of all sites have your best interests in mind. Find out who is responsible for the site you are examining. If you do not recognize the name of the organization which sponsors the site, look for information about it – on the site itself and elsewhere on the Web, using a search engine – and take that knowledge into consideration as you evaluate the site. An example of a site that most Idaho librarians find useful is Libraries Linking Idaho, www.lili.org/, for the many resources it offers you and your patrons. Other organizational sites, however, may reflect opinions and beliefs that most people would find offensive.
– is assigned to organizations involved in Internet infrastructure activities, such as Internet service providers, Web hosting, and domain name registration. Examples include Earthlink (www.earthlink.net/) a service provider, and InterNIC (www.internic.net) for domain name registration services.
– used exclusively by the U.S. military. It includes the Department of Defense web site, (www.defenselink.mil), the Air Force, (www.af.mil), Army, (www.army.mil), Marine Corps, (www.usmc.mil), and Navy (www.navy.mil). However, the Web site for the Idaho Military Division (National Guard) is www.idarng.com.
.us
(United States), .ca (Canada), .au (Australia), .uk
(United Kingdom), and .gb (Great Britain) are examples of the two-letter
suffixes used by countries throughout the world. By watching for this type
of suffix, you can easily determine the country of origin of a Web site. There
are several Internet sites where you can find a complete list of these
suffixes, such as www.checkdomain.com. If no country suffix is included in the URL,
you are most likely looking at a United States site.
The next, and final, section in this course lists some additional sources of information on web site evaluation.
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