Google indexes over 8 billion web pages. Many of these web pages contain good, reliable information you cannot find anywhere else but many of them contain unreliable information. If you want to find what most people would consider reliable, authoritative, and balanced information on the web, Google provides a variety of search techniques you can use to enhance your chances of finding it.

Information that is reliable and authoritative does not mean its presenters do not use it to support a point of view on the subject, it just means that point of view rests on a better foundation.

The top level domain -- indicated by the two or three characters before the first slash in a domain name -- indicates the type of sponsor or purpose behind the web site. A list of top level domains is available from the Internet Committee for Assigned Names and Numbers.

A list of country codes used in top level domain names is available from the Internet Assigned Numbers Authority. In general, the following top level domains tend to have more reliable information since the information posted on them is likely to represent the organization rather than an individual and therefore tends to undergo more review.

.edu --

U.S. educational institutions. Many reports, studies, and data issued by college and unversity departments are posted on .edu sites. Also, individual faculty members may have their published and unpublished materials posted on their institution's site. To restrict your Google search to.edu sites go to Advanced Search and enter .edu in the Domain window.

.org --

Organizations that do not fit into other top level domains. Most of these are non-profit organizations such as the American Diabetes Association (http://www.diabetes.org) and the United Nations Educational, Scientific and Cultural Organization (http://www.unesco.org). Such organizations may publish information about themselves, their work, and be clearinghouses for reliable information about their area of focus (e.g., about diabetes). To restrict your Google search to .org sites go to Advanced Search and enter .org in the Domain window.

.gov --

U.S. government agencies. This domain is also used by some states in combination with a state abbreviation -- e.g., many State of Colorado web pages have domains ending in .co.us -- or use the name of the state followed by .gov -- e.g., .colorado.gov. Some states use both forms. To restrict your Google search to .gov sites go to Advanced Search and enter .gov in the Domain window. To restrict your Google search to state web sites go to Advanced Search and enter .xx.gov in the Domain window where xx is the two letter state abbreviation or use the form .[name of state].gov.

(document type) independently or in combination with a top level domain. Many reports, articles, and other documents containing reliable information tend to be posted to the web as a .pdf (Portable Document File) or .doc (Microsoft Word file).

To restrict your Google search to certain file types go to Advanced Search and select a type from the File Format window. You can also enter a certain top level domain in the Domain window to use in combination with the file type.