Browsers are programs that provide access to Web resources. This software connects you to remote computers, opens and transfers files, displays text and images, and provides in one tool an uncomplicated interface to the Internet and Web documents. Two well-known browsers are Netscape Navigator and Microsoft Internet Explorer. For browsers to connect to other resources, the location or address of the resources must be specified. These addresses are called Uniform Resources Locators (URLs). Following the Domain Name System (DNS), all URLs have at least three basic parts. The first part presents the protocol used to connect to the resource. The protocol http:// is by far the most common. The second part presents the domain name or the name of the server where the resource is located. The server is identified as www.aol.com. (Many URLs have additional parts specifying directory paths, file names, and pointers.) The last part of the domain name following the dot (.) is the domain code. It identifies the type of organization. For example, com indicated a commercial site.

The URL http://www.aol.com connects your computer to a computer that provides information about America Online (AOL). These informational locations on the Web are called Web sites. Moving from one Web site to another is called surfing.

Once the browser has connected to a Web site, a document file is sent to your computer. This document contains Hypertext Markup Language (HTML) commands. The browser interprets the HTML commands and displays the document as a Web page. Typically, the first page of a Web site is referred to as its home page. [1]The home page presents information about the site along with references and hyperlinks, or connections to other documents that contain related information such as text files, graphic images, audio, and video clips.

These documents may be located on a nearby computer system or on one halfway around the world. The references appear as underlined and colored text and /or images on the Web page. To access the referenced material, all you do is click on the highlighted text or image. A link is automatically made to the computer containing the material, and the referenced material appears.

Communication is the most popular Internet activity. The impact of electronic communication cannot be overestimated. At a personal level, friends and family can stay in contact with one another even when separated by thousands of miles. At a business level, electronic communication has become standard and many times preferred way to stay in touch with suppliers, employees, and customers.

You can communicate with anyone in the world who has an Internet address or e-mail account with a system connected to the Internet. All you need is access to the Internet and an e-mail program. Two of the most widely used e-mail programs are Microsoft's Outlook Express and Netscape's Navigator.

Suppose that you have a friend, Anny, who is going to the University of Southern California. You and Anny have been planning a trip for the upcoming break. You have heard there are some inexpensive airfare deals online. To save money, you and Anny agree to research these offers and e-mail each other your findings.

A typical e-mail message has three basic elements: header, message and signature. The header appears first and typically includes the following information:

Addresses: Addresses of the persons sending, receiving,and,optionally,anyone else who is to receive copies.

Subject: A one-line description, used to present the topic of the message. Subject lines typically are displayed when a person checks his or her mail-box.

Attachments: Many e-mail programs allow you to attach files such as documents and worksheets. If a message has an attachment, the file name appears on the attachment line.

The letter or message comes next. It is typically short and to the point. Finally, the signature line provides additional information about the sender. Typically, this information includes the sender's name, address, and telephone number.

Following the domain name system discussed earlier, e-mail addresses have two basic parts. The first part is the user's name and the second part is the domain name, which includes the domain code.

You can also use e-mail to communicate with people you do not know but with whom you wish to share ideas and interests. You can participate in discussions and debates that range from general topics like current events and movies to specialized forums like computer troubleshooting and Star Trek.

Mailing lists allow members of a mailing list to communicate by sending messages to a list address. Each message is then copied and sent via e-mail to every member of the mailing list. To participate in a mailing list, you must first subscribe by sending an e-mail request to the mailing list subscription address. Once you are a member of a list, you can expect to receive e-mail from other on the list. You may find the number of messages to be overwhelming. If you want to cancel a mailing list, send an e-mail request to "unsubscribe" to the subscription address.

Newsgroups, unlike mailing lists, use a special network of computers called the Usenet. Each of these computers maintains the newsgroups listing. There are over 10,000 different newsgroups organized into major topic areas that are further subdivided into subtopics. Contributions to a particular newsgroup are sent to one of the computers on the Usenet. This computer saves the messages on its system and periodically shares all its recent messages with the other computers on the Usenet. Unlike mailing lists, a copy of each message is not sent to each member of a list. Rather, interested individuals check contributions to a particular newsgroup, reading only those of interest. There are thousands of newsgroups covering a wide variety of topic areas.

Chat groups allow direct "live" communication. To participate, you join a chat group, select a channel or topic, and communicate live with others by typing words on your computer. Other members of your channel immediately see those words on their computers and can respond in the same manner. One popular chat service is called Internet Relay Chat (IRC). This software is available free from several locations on the Internet. Using the chat-client software, you log on to the server, select a channel or topic in which you are interested, and begin chatting. To participate, you need access to a server or computer that supports IRC. This is done using special chat-client software.

Instant messaging, like chat groups, allows one or more people to communicate via direct, "live" communication. Instant messaging, however, provides greater control and flexibility than chat groups. To use instant messaging, you specify a list of friends, or "buddies", and register with an instant messaging server. Whenever you connect to the Internet, you use special software to tell your messaging server that you are online too. It notifies you if any of your buddies are online. At the same time, it notifies your buddies that you are online. You can then send messages back and forth to one another instantly.

Before you submit a contribution to a discussion group, it is recommended that you observe or read the communications from others. This is called lurking. By lurking, you can learn about the culture of a discussion group. For example, you can observe the level and style of the discussions. You may decide that a particular discussion group is not what you were looking for-in which case, unsubscribe. If the discussions are appropriate and you wish to participate, try to fit into the prevailing culture. Remember that your contributions will likely be read by hundreds of people.