Usenet is a world-wide threaded messaging network, developed by graduate students at Duke University in 1979, where users interact on a variety of subjects. Initially developed using three small servers to share research information, Usenet is now the largest decentralized information resource in the world. Usenet is not governed by any single body and has no defined rules other than the Network News Transfer Protocol, which specifies network connections and commands to transfer data. While many Usenet servers send information across the Internet, Usenet is a separate entity from the Internet and does not require an Internet connection.

The heart of Usenet is the information, or articles, posted by users in a format similar to e-mail. Users post articles as threads to one or more of over 15,000 newsgroups worldwide. Content of some newsgroups is moderated, while many are not. Information is accessed over Usenet by the exchange of newsgroups between hosting servers.

While some web sites allow browsing and responding to newsgroups on web pages, access to newsgroups typically requires software besides a standard browser, referred to as a news reader. Netscape Navigator and Communicator include news readers. Microsoft Internet Explorer 4.0 allows newsgroup access when Outlook Express software is installed. Users of other browsers need to install additional news reader software. Many shareware news readers are available, and links for a few can be found on Yahoo at www.yahoo.com/Computers_and_Internet/Software/Internet/Usenet/.

URLs for newsgroups typically reflect the topic for the group and follow a hierarchical scheme. Newsgroup URLs begin with a general category such as "comp" for computers and software, or "sci" for science and technical topics, and get more specific from there. For example, the URL "sci.physics" deals with physics in general, while "sci.physics.research" deals specifically with physics research. (For a list of URLs and their subjects, see table.)

Many search engines (www.altavista.com and www.excite.com) provide the option to search Usenet newsgroups. One search engine, Deja News (www.dejanews.com) is dedicated to Usenet searches. Usenet searches are just like web searches—just enter a keyword or phrase and the search engine goes to work. The results page of a Usenet search provides links to articles. Viewing articles by way of a search engine does not require a dedicated news reader. The search engines convert articles to hypertext transfer protocol (HTTP) format and display them as pages in a web browser. Pages do not allow direct reply to an article, but will provide hypertext links to the newsgroups that contain the articles. When using a browser with a news reader, clicking on a link will open the selected newsgroup in the news reader.

Newsgroups allow users to interact with others by responding to articles or by posting articles requesting comments or input on a topic. Before getting involved in a newsgroup, it's a good idea to read the FAQ (frequently asked questions) for that group. Many use FAQs to communicate the purpose and rules for that newsgroup. Some expect users to deal only with very specific topics or respond to other articles in a particular way. If it has one, a newsgroup's FAQ is regularly posted. Another place to find out if a newsgroup has a FAQ is to look at the "answers" group of the main category—"sci.answers," for example.

Anyone interested in learning more about Usenet should check a local library or bookstore. There are many books available with more detail on getting around Usenet and how Usenet works.