the act of impersonating a user or a machine. For example, IP spoofing is the act of attaching a computer to the Internet using an IP address assigned to a different computer, thereby intercepting communications intended for the other machine.

laws pertaining to computers. An important principle is that computers are not exempt from the pre-existing laws. For instance, computer users must obey laws against fraud, misrepresentation, harassment, eavesdropping, theft of services, and tampering with other people's property, even if the laws do not specifically mention computers.

Further, many jurisdictions have specific laws against computer trespass and similar acts.

1. a set of thousands of newsgroups (discussion forums) distributed via the Internet (formerly distributed through the Usenet wide-area network). Newsgroups have descriptive names such as sci.astro. amateur and are arranged into hierarchies (classifications), of which the main ones are:
   

   news.	for announcements about Usenet itself;
   comp.	for computer science and technology;
   sci.	for other academic topics (including humanities);
   soc.	for cultural interest groups;
   rec.	for hobbies and sports;
   talk.	for wide-ranging discussions, often heated;
   misc.	for a few topics that don't fit elsewhere;
   alt .	for trial newsgroups and "alternative" topics.

   
   Usenet has no headquarters; the messages are copied back and forth among numerous servers. However, in recent years, participation in this network has declined, and many users prefer to access the newsgroups through http://groups.google.com (Google Groups). This sometimes creates the false impression that Google runs the whole system.
2. a wide-area network for UNIX machines that formerly exchanged files by modem through the UUCP ("UNIX-to-UNIX copy") command. Usenet addresses were of the form
   psuvax!ugacc!aisun1!mcovingt
   (which means "user mcovingt on machine aisun1, which can be reached through ugacc, which can be reached through psuvax"). Usenet has been supplanted by the Internet.

the conventional practices that make the Internet usable. More than just politeness, netiquette involves fundamental respect for the rights of other users who are helping pay the cost of running the network.

For example, it is unacceptable to post off-topic material in newsgroup, be rude during chats, ask people to do your homework for you, or bother them with commercial solicitations.

the practice of registering an Internet domain name with the intention of reselling the domain name rights to a corporation or individual. For example, you might want to register www.ford.com for yourself in the hope that Ford Motor Company would then buy it from you. Also called domain name hijacking and cybersquatting.

system of linked smaller computer networks, international in scope, that facilitates data communication such as file transfer, electronic mail, and newsgroups between different entities.

a computer term for unwanted e-mail. In a Monty Python television skit, a group of Vikings in a restaurant sing about the meat product, "Spam, spam, spam, spam, spam, spam, spam, spam, lovely spam Wonderful spam" until told to shut up. As a result, something that keeps being repeated to great annoyance was called spam, and computer programmers picked up on it.

Protect your e-mail address.Spammers either buy lists of e-mail addresses or use software programs that mine the addresses from the Internet. If your address is posted in discussion groups, on Web sites, in chat rooms, etc., chances are it will end up on one or more of these lists. Only post your address publicly when absolutely necessary.
Set up multiple e-mail accounts.If you do participate regularly in on-line activities where you post your address, set up another e-mail account. Reveal it only to close friends and family.
Use spam filters.Many e-mail programs, such as Outlook Express, have built-in tools that block messages sent from certain addresses or that filter messages based on key words you define. Check the on-line help files for your e-mail software.
Use anti-spam software.You can install software designed to eliminate spam. Some work by matching incoming messages against a list of known spammers; others block messages that don't match an approved list of acceptable addresses. Check out the latest anti-spam programs at Download.com.
Report violators.A number of government agencies and private groups accept complaints. Whether they can do anything to stop the deluge is an unanswered question. Forward spam to the Federal Trade Commission at uce@ftc.gov.
Source: about.com

publications or images whose primary purpose is to stimulate sexual appetite.See also indecency; obscenity.

Even the most innocent Internet user occasionally stumbles upon pornography. Some pornographers send advertisements to all the email addresses they can obtain or make up (seespam). (Such e-mail does not indicate that the recipient has been viewing pornographic web pages, even if it says that it does.) Others rig their web pages so that search engine will lead users to them who are looking for something else.

Many individuals find pornography strongly addictive. The purpose of pornography is to make money, and the only reason it is given away free is to get people "hooked" so that they will pay for more.

In the United States, most of the pornography on the Internet is legal, but sexually explicit images of children are not, and images of sexual behavior may not be legal, depending on local laws. (See obscenity; computer law.) Law enforcement is hampered by the difficulty of determining the physical locations of web sites. Note however that because the laws prohibit distribution of obscene material, a link to an obscene site can itself be illegal.

There have been various efforts to keep pornography from reaching children and unwilling audiences. The Communications Decency Act of 1996 was struck down because it assumed, incorrectly, that Internet service providers can control the information sent through their computers; replacement legislation has been proposed. Schools and libraries sometimes use "filtering" software to block access to known pornographic web sites, but the filtering process is imperfect. See ICRA.

Pornography is associated with credit card fraud and other crimes. Several Internet pornography vendors have been caught making unauthorized charges to credit card numbers, presumably expecting the victims to be too embarrassed to complain. In some cases the numbers were stolen or made up and belonged to people who had never had any contact with the vendors.

It is naive to describe pornography as "victimless." The most obvious victims are the individuals who become addicted, and whose relationships and even marriages are damaged. The young people hired to pose for pornographic pictures are also victims of exploitation.

sexually explicit material that can be prohibited by law. In 1973 the Supreme Court of the United States ruled that material is obscene if the average person, using contemporary community standards, would find that its primary purpose is to stimulate sexual appetite ("the prurient interest"); it depicts sexual behavior defined as offensive by specific laws; and it "lacks serious, literary, artistic, political or scientific value." Contrast indecency.

the practice of trying to flood an obnoxious person with gigantic amounts of e-mail. This is a very bad idea for several reasons. It clogs up facilities needed by other people, not just the intended recipient. More importantly, people who act obnoxious on the Internet generally falsify their addresses, thereby bringing down floods of wrath upon innocent victims.