From C to D

Cable modem

A device that permits one-way or two-way high speed data communication over a cable television system for purposes such as Internet access .


Memory used to temporarily store the most frequently requested content/files/pages in order to speed its delivery to the user. Cache can be local(i.e. on a browser)or on a network. In the case of local cache, most computers have both memory(RAM), and disk(hard drive)cache. Today, Web browsers cause virtually all data viewed to be cached on a user’s computer.

Cache busting

The process by which sites or servers serve content or HTML in such a manner as to minimize or prevent browsers or proxies from serving content from their cache. This forces the user or proxy to fetch a fresh copy for each request. Among other reasons, cache busting is used to provide a more accurate count of the number of requests from users.

Cached ad impressions

The delivery of an advertisement to a browser from local cache or a proxy server’s cache. When a user requests a page that contains a cached ad, the ad is obtained from the cache and displayed.


The process of copying a Web element(page or ad)for later reuse. On the Web, this copying is normally done in two places: in the user’s browser and on proxy servers. When a user makes a request for a Web element, the browser looks into its own cache for the element; then a proxy, if any; followed by the intended server. Caching is done to reduce redundant network traffic, resulting in increased overall efficiency of the Internet.

CARU(The Children’s Advertising Review Unit)

Division of the Council of Better Business Bureaus that reviews advertising and promotional material directed at children in all media. See for more information.

CGI script(Common Gateway Interface)

CGI’s are used to allow a user to pass data to a Web server, most commonly in a Web-based form. Specifically, CGI scripts are used with forms such as pull-down menus or text-entry areas with an accompanying submit button. The input from the form is processed by a program(the CGI script itself)on a remote Web server.


1) A band of similar content;
2) A type of sales outlet(also known as channel of distribution), for example retail, catalogue, or e-commerce.


Online interactive communication between two or more people on the Web. One can “talk” in real time with other people in a chat room, but the words are typed instead of spoken.

Chat room

An area online where you can chat with other people in real-time.

Click down

The action of clicking on an element within an ad and having another file displayed on the user’s screen, normally below or above the initial ad. Click down ads allow the user to stay on the same Web page and provide the advertiser a larger pallet to communicate their message.

Click rate

Ratio of ad clicks to ad impressions.


1) Metric which measures the reaction of a user to an Internet ad. There are three types of clicks: click-throughs; in-unit clicks; and mouseovers;
2)the opportunity for a user to download another file by clicking on an advertisement, as recorded by the server;
3)the result of a measurable interaction with an advertisement or key word that links to the advertiser’s intended Web site or another page or frame within the Web site;
4)metric which measures the reaction of a user to hot-linked editorial content. See for ad campaign measurement guidelines. See also ad click, click-through, in-unit clicks and mouseover.


1) The electronic path a user takes while navigating from site to site, and from page to page within a site;
2) A comprehensive body of data describing the sequence of activity between a user’s browser and any other Internet resource, such as a Web site or third party ad server.


The action of following a hyperlink within an advertisement or editorial content to another Web site or another page or frame within the Web site. Ad click-throughs should be tracked and reported as a 302 redirect at the ad server and should filter out robotic activity.


Similar to click down or click. But more commonly, click-withins are ads that allow the user to “drill down” and click, while remaining in the advertisement, not leaving the site on which they are residing.


A computer that submits an information request to a server on behalf of a user or proxy.

Client-initiated ad impression

One of the two methods used for ad counting. Ad content is delivered to the user via two methods-server-initiated and client-initiated. Client-initiated ad counting relies on the user’s browser for making requests, formatting and re-directing content. For organizations using a client-initiated ad counting method, counting should occur at the publisher’s ad server or third-party ad server, subsequent to the ad request, or later, in the process. See server-initiated ad impression.


Short for compressor/decompressor. Codecs are computer algorithms that are used to compress the size of audio, video, and image files. Because these compressed files are much smaller, they do not require as much bandwidth when they are streamed or stored on a computer. The same codec that originally compressed the file must be used to decompress and open the file.

Communication error

The failure of a Web browser/Web server to successfully request/transfer a document.

Content integration

Advertising woven into editorial content or placed in a contextual envelope. Also known as “Web advertorial”.


A file on the user’s browser that uniquely identifies the user’s browser. There are two types of cookies: persistent cookies and session cookies. Session cookies are temporary and are erased when the browser exits. Persistent cookies remain on the user’s hard drive until the user erases them or until they expire.

Cookie buster

Software that blocks the placement of cookies on a user’s browser.

COPPA(Children’s Online Privacy Protection Act)

Congress enacted the COPPA in 1998 to prohibit unfair or deceptive acts or practices in connection with the collection, use, or disclosure of personally identifiable information from and about children on the Internet. Section 6502(b)(1)of the Act sets forth a series of general privacy protections to prevent unfair or deceptive online information collection from or about children, and directs the Commission to adopt regulations to implement those protections. The Act requires operators of Web sites directed to children and operators who knowingly collect personal information from children to:(1)Provide parents notice of their information practices;(2)obtain prior verifiable parental consent for the collection, use, and/or disclosure of personal information from children(with certain limited exceptions for the collection of “online contact information,” e.g., an e-mail address);(3)provide a parent, upon request, with the means to review the personal information collected from his/her child;(4)provide a parent with the opportunity to prevent the further use of personal information that has already been collected, or the future collection of personal information from that child;(5)limit collection of personal information for a child’s online participation in a game, prize offer, or other activity to information that is reasonably necessary for the activity; and(6)establish and maintain reasonable procedures to protect the confidentiality, security, and integrity of the personal information collected.

COPPR(Children’s Online Privacy Protection Rule)

Issued by the FTC in October 1999 the Children’s Online Privacy Protection Rule went into effect on April 21, 2000, and implements the requirements of the COPPA by requiring operators of websites or online services directed to children and operators of Web sites or online services who have actual knowledge that the person from whom they seek information is a child(1)to post prominent links on their Web sites to a notice of how they collect, use, and/or disclose personal information from children;(2)with certain exceptions, to notify parents that they wish to collect information from their children and obtain parental consent prior to collecting, using, and/or disclosing such information;(3)not to condition a child’s participation in online activities on the provision of more personal information than is reasonably necessary to participate in the activity;(4)to allow parents the opportunity to review and/or have their children’s information deleted from the operator’s database and to prohibit further collection from the child; and(5)to establish procedures to protect the confidentiality, security, and integrity of personal information they collect from children. As directed by the COPPA, the Rule also provides a safe harbor for operators following Commission-approved self-regulatory guidelines. See for more information.


Printed text in an advertisement.

Count audit

See activity audit.


Cost of advertising based on a visitor taking some specifically defined action in response to an ad. “Actions” include such things as a sales transaction, a customer acquisition, or a click.


The cost an advertiser pays to acquire a customer.


Cost of advertising based on the number of clicks received.


Cost of advertising based on the number of database files(leads)received.


Media term describing the cost of 1,000 impressions. For example, a Web site that charges $1,500 per ad and reports 100,000 visits has a CPM of $15($1,500 divided by 100).

CPM pricing model

Pricing model based on the cost of delivering ad impressions. See CPM and Pay-per-Impression.


Cost of advertising based on the number of orders received. Also called Cost-per-Transaction.


The advertiser’s cost to generate one sales transaction. If this is being used in conjunction with a media buy, a cookie can be offered on the content site and read on the advertiser’s site after the successful completion of an online sale.


Cost per view – for video advertising.


See CPO(Cost-per-Order).

CPTM(Cost per Targeted Thousand Impressions)

Implying that the audience one is trying to reach is defined by particular demographics or other specific characteristics, such as male golfers age 18-25.The difference between CPM and CPTM is that CPM is for gross impressions, while CPTM is for targeted impressions.


A software program which visits virtually all pages of the Web to create indexes for search engines. They are more interested in text files than graphic files. See also spider, bot, and intelligent agent.


Customer relationship marketing. Marketing specifically targeted to increasing brand loyalty.

Cyber Cafe

A place which contains computers with access to the Internet and which is available to the public.

Daughter window

An ad that runs in a separate ad window associated with a concurrently displayed banner. In normal practice, the content and banner are rendered first and the daughter window appears thereafter.


Common characteristics used for population or audience segmentation, such as age, gender, household income, etc.

Digital signatures

Signatures for electronic documents. They establish identity and therefore can be used to establish legal responsibility and the complete authenticity of whatever they are affixed to–in effect, creating a tamper-proof seal.

Digital Video Server

A robust, dedicated computer at a central location that receives command requests from the television viewer through a video-on-demand application. Once it receives this request, it then instantly broadcasts specific digital video streams to that viewer.


Successful download giving the user an opportunity to see.

DHTML(Dynamic Hypertext Markup Language)

An extended set of HTML commands which are used by Web designers to create much greater animation and interactivity than HTML.

Domain name

The unique name that identifies an Internet site. Every domain name consists of one top or high-level and one or more lower-level designators. Top-level domains(TLDs)are either generic or geographic. Generic top-level domains include .com(commercial), .net(network), .edu(educational), .org(organizational, public or non-commercial), .gov(governmental), .mil(military); .biz(business), .info(informational),.name(personal), .pro(professional), .aero(air transport and civil aviation), .coop(business cooperatives such as credit unions)and .museum. Geographic domains designate countries of origin, such as .us(United States), .fr(France), .uk(United Kingdom), etc.

DPO(Distinct Point of Origin)

A unique address from which a browser connects to a Web site on the Internet.

Drill down

When an online user accesses more and more pages of the Web site, i.e., he or she goes deeper into the content of the site.

DSL(Digital Subscriber Line)

A high-speed dedicated digital circuit from a given location to the telephone company’s central office, using normal copper telephone lines. DSL provides a separate channel for voice and fax, which means that phone calls and faxes can be carried at the same time high-speed data is flowing across the line. DSL is a general term that includes several variations: ADSL(Asymmetric Digital Subscriber Line), ranging up to 1.5 Mbps; HDSL(High-bit-rate Digital Subscriber Line), 1.5 Mbps; SDSL(Single-line Digital Subscriber Line), 1.5 Mbps; VDSL(Very high-data-rate Digital Subscriber Line), ranging up to 2.3 Mbps; and RDSL(Rate Adaptive Digital Subscriber Line), various speeds.

DVR(Digital Video Recorder)

A high capacity hard drive that is embedded in a set-top box, which records video programming from a television set. These DVRs are operated by personal video recording software, which enables the viewer to pause, fast forward, and manage all sorts of other functions and special applications.

Dynamic ad placement

The process by which an ad is inserted into a page in response to a user’s request. Dynamic ad placement allows alteration of specific ads placed on a page based on any data available to the placement program. At its simplest, dynamic ad placement allows for multiple ads to be rotated through one or more spaces. In more sophisticated examples, the ad placement could be affected by demographic data or usage history for the current user.

Dynamic IP address

An IP address that changes every time a user logs on to the Internet.

Dynamic rotation

Delivery of ads on a rotating, random basis so that users are exposed to different ads and ads are served in different pages of the site.