.COM - When these letters appear as the last part of a Web address, it indicates that the host computer is run by a commercial organization, probably in the United States.

Cache - A temporary storage area for frequently-accessed or recently-accessed data.Having certain data stored in cache speeds up the operation of the computer.There are two kinds of cache: internal (or memory cache) and external (or disk cache).Internal cache is built into the CPU, and external cache is on the motherboard.When an item is called for, the computer first checks the internal cache, then the external cache, and finally the slower main storage.

Cafe - Popular today are Internet Cafe's where one may go and dine and also play on the Internet.

Carrier - A continuous frequency capable of being either modulated or impressed with another information-carrying signal. Carriers are generated and maintained by modems via the transmission lines of the telephone companies.

Cascade - A way of arranging open windows on the computer screen so that they overlap diagonally with each title bar showing.

CD Rom - A computer disk that can store large amounts of information; generally used on computers with CD-ROM drives. "CD-ROM" stands for "Compact Disk Read Only Memory". That means it can only play back information, not record or save material.

CCITT - A French acronym for the International Telephone and Telegraph Consultative Committee. This international organization defines the standards for telephone equipment such as the Bell 212A standard for 1200 baud, CCITT V.22 for 2400 baud and CCITT V.32 for 9600 baud.

CGI (Common Gateway Interface) - the specification for how an HTTP web server should communicate with server gateway applications. Usually a CGI program is a small program that takes data from a web server and does something with it, like putting the content of a form into an e-mail message, or turning the data into a database query.

Chat - Refers to a service provided by many online systems where users may communicate real-time in an interactive conversation by typing messages to other users in the chat 'channel' A system by which two Internet users can “talk” with each other via typing words. You see the other person’s message almost instantly and vice versa. (This is unlike e-mail, in which you send your words, and wait for the recipient to receive, read and then respond).

Clickstreams or Clickthough - The paths a user takes as he or she navigates a Web page or cyberspace in general. Advertisers and online media providers have developed software that can track users’ clickstreams. The percentage of ad views that result in a user clicking on an ad.

Client System (or Client) - Another word for the user's computer on the Internet or BBS. A PC that uses hardware and/or services that reside on another computer. Also known as a workstation or desktop.

Client Based Filter - A software program that you install on your own computer to block access to inappropriate material, prevent kids from accessing the Internet at certain times, or to prevent kids from revealing personal information. See also "filtering software" and "blocking software."

Cold Boot - Booting the system from power off. Same as hard boot.

Cold Fusion - ColdFusion is a visual programming, database and debugging tool. It is used for building Web applications.ColdFusion offers integration with databases, e-mail, XML and other enterprise technology.

Content - The information contained in a Web site, including the structure in which it is presented. Web sites often get judged and rated on the quality, quantity and navigational flow of this information.

Cookie - The most common meaning of “Cookie” on the Internet refers to a piece of information sent by a Web Server to a Web Browser that the Browser software is expected to save and to send back to the Server whenever the browser makes additional requests from that Server. When a Server receives a request from a Browser that includes a Cookie, the Server is able to use the information stored in the Cookie and customize a response based on information from a previous connection.

Conference - An area of public messages on a Bulletin Board System, usually with a particular topic and, often, a conference host or moderator to guide the discussion. Also called Folder, SIG (for Special Interest Group) or Echo.

CPS - Characters Per Second. A transfer rate estimated from the bit rate and length of each character. If each character is 8 bits long and includes a start and stop bit for Asynchronous transmission, each character needs 10 bits to be sent. At 2400 baud it is transmitted at approximately 240 CPS.

CPU (Central Processing Unit) - The CPU controls the operation of a computer.Units within the CPU perform arithmetic and logical operations and decode and execute instructions.In microcomputers, the entire CPU is on a single chip.

Crawler - A computer program that retrieves online documents and the references linked to them, and may perform indexing.

CRC (Cyclical Redundancy Check) - An error-detection technique consisting of a cyclic algorithm performed on each block of data at the sending and receiving end of the transmission. As each block is received, the CRC value is checked against the CRC value sent along with the block. Many protocols including XMODEM-CRC and ARQ will request a resend until the block is received correctly.

Cut and Paste - Deleting a block of material (text or graphics, or both) from one place and moving it to another place.The expression is taken from production room layout, where originally cutting and pasting was done by hand.

Cyber Cafe - A cafe where online services are available.Patrons can surf the Internet or play computer games, while meeting others with similar interests and sharing computer knowledge.Cybercafes originated in New York and are now available around the world; travelers can use cybercafes to connect to online services when away from home.

Cyberspace - The “area” in which computer users travel when “navigating” around on a network. A term coined by novelist William Gibson to describe the world of data created by million of computers worldwide

Cybersquatter - A person who buys a domain name corresponding to a famous brand name or trademark, hoping to resell it for big bucks when the company wants to open a website.