Internet "Saboteurs"

Finger: An Internet tool for locating people on other sites. Finger can also be used to give access to non-personal information, but the most common use is to see if a person has an account at a particular site. The most famous finger site was a Coke machine at Carnegie-Mellon University that students had wired to the Internet. They could then finger the machine and find out how many bottles remained and how long they had been in the machine so they wouldn't walk all the way there and find an empty machine or warm soda.
Firewall: A combination of hardware and software that separates a LAN into two or more parts for security purposes. A firewall is commonly used to separate a network from the Internet.
Netizen: A term referring to a citizen of the Internet, or someone who uses networked resources. The term connotes civic responsibility and participation.
Spam (or Spamming): To send a message or advertisement to a large number of people who did not request the information, or to repeatedly send the same message to a single person. "Spamming" is considered very poor Netiquette. CAUCE (The Coalition Against Unsolicited Commercial Email) is an organization dedicated to removing spam from the Internet.
Spyware: A somewhat vague term generally referring to software that is secretly installed on a users computer and that monitors use of the computer in some way without the users' knowledge or consent. Most spyware tries to get the user to view advertising and/or particular web pages. Some spyware also sends information about the user to another machine over the Internet.
Spyware is usually installed without a users' knowledge as part of the installation of other software, especially software such as music sharing software obtained via download.
Trolling: The act of deliberately posting false or inflammatory information in order to start a flame war or cause aggravation to others.
Trojan Horse: A computer program is either hidden inside another program or that masquerades as something it is not in order to trick potential users into running it. For example a program that appears to be a game or image file but in reality performs some other function. The term "Trojan Horse" comes from a possibly mythical ruse of war used by the Greeks sometime between 1500 and 1200 B.C. A Trojan Horse computer program may spread itself by sending copies of itself from the host computer to other computers, but unlike a virus it will (usually) not infect other programs.
Virus: A chunk of computer programming code that makes copies of itself without any concious human intervention. Some viruses do more than simply replicate themselves, they might display messages, install other software or files, delete software of files, etc. A virus requires the presence of some other program to replicate itself. Typically viruses spread by attaching themselves to programs and in some cases files, for example the file formats for Microsoft word processor and spreadsheet programs allow the inclusion of programs called "macros" which can in some cases be a breeding ground for viruses.
Worm: A worm is a virus that does not infect other programs. It makes copies of itself, and infects additional computers (typically by making use of network connections) but does not attach itself to additional programs; however a worm might alter, install, or destroy files and programs.