C Class IP - This is the third block of numbers found in an IP Address.

Cache - A copy of web pages stored in a search engine database.

Caching - The process of storage of Web files for later re-use at a point more quickly accessed by the end user. It what search engines do with the information on certain types of web pages, save the information in database.

CAD - 3 Letter Currency Code for Canadian Dollars.

CAD - Abbreviation for Computer Aided Design and also file extension: filename.cad

Call To Action - A link, which when clicked on sends the user to a different page, typically an online form page, or other page where the user inputs information. A link otherwise known as a hyperlink. Call-to-action links in Internet marketing campaigns guide the reader to a new action step. Call-to-action hyperlinks could lead a prospect to a new Web page, an email form and a text section within a page or a shopping cart. Correctly written, call-to-action links increase micro-conversion rates and can affect keyphrase relevancy.

CAP - Content Acquisition Program.

CAPTCHA - Abbreviation for Completely Automated Public Turing test to tell Computers and Humans Apart.

Cascading Style Sheets - A data format used for adding style (e.g. fonts, colors and spacing) to Web pages. (see also: CSS)

CD - Compact Disk

CDR - Compact Disk Recordable

CFM - Cold Fusion Markup, also file extension filename.cfm

CFML - Cold Fusion Markup Language

CFO - Chief Financial Officer

CGI - Common Gateway Interface, also file extension filename.cgi

CGI-BIN - Common Gateway Interface - Binary (/cgi-bin/)

CHF - 3 Letter Currency Code for Switzerland Francs

Click Arbitrage - Purchasing PPC ads and hoping that traffic leaves with a click on your ads.

Click Fraud - Clicking on competitor’s ads just to drive up their PPC costs.

Click Pirates - People who click on ads, knowingly and proudly, stealing from advertisers, as they encourage others to join with them in this quest.

Click-Pimping - This should be known as Seamlessly Integrating Contextually Relevant Infotisements to Maximize ROI.

Click Through - The process of clicking through an online advertisement to the advertiser's destination.

Click-through - Same as the Click Through

Clickthrough Rate - The average number of click-thorough per hundred ad impressions, expressed as a percentage. For example: 100 people do a web search and in search result they see links to a variety of web pages. 17 out of the 100 people choose one particular link. That link then has a 17% of Clickthrough Rate.

Cloaking - It is an unethical SEO marketing practice of tricking the search engine into indexing different content than the user will see. A technique that shows keyword stuffed pages to a search engine, but a real page to a human user. A website that sends different content to the search engine than it sends to the end-user. This is spam trickery.

Also known as stealth, a technique used by some Web sites to deliver one page to a search engine for indexing while serving an entirely different page to everyone else. There are opposing views as to whether or not cloaking is ethical. Opponents see it as a bait-and-switch, where a Web server is scripted to look out for search an engine that is spidering in order to create an index of search results. The search engine thinks it is selecting a prime match to its request based on the meta tags that the site administrator has input. However, the search result is misleading because the meta tags do not correspond to what actually exists on the page. Some search engines, such as Lycos, Hotbot and Excite, even ban cloaked Web sites. Proponents of cloaking assert that cloaking is necessary in order to protect the meta data, as only the spider is supplied with the meta tags.

In terms of search engine marketing, this is the act of getting a search engine to record content for a URL that is different than what a searcher will ultimately see. It can be done in many technical ways. Several search engines have explicit rules against unapproved cloaking. Those violating these guidelines might find their pages penalized or banned from a search engine's index. As for approved cloaking, this generally only happens with search engines offering paid inclusion program. Anyone offering cloaking services should be able to demonstrate explicit approval from a search engine about what they intend to do. If not, then they should then have explained the risks inherent of unapproved cloaking.

Clustering - In search engine search results pages, clustering is limiting each represented website to one or two listings.

CMS - Abbreviation for Content Management System

CMYK - Abbreviation for the color palette Cyan - Magenta - Yellow - Black

Code 301 - Permanent Redirect

Code 302 - Temporary Redirect. Can get your site delisted.

Code 404 - Page not found

Code Swapping - Changing content when good rankings are made.

ColdFusion Hosting - Web hosting that supports ColdFusion, a web application language introduced by Allaire and currently owned by Macromedia.

Colocated Hosting - When one party houses their web server(s) at another company's location for Internet connectivity.

Comment Spam - Posting in someone's blog for the purpose of attracting traffic to your site (via search engines).

Comment Tags - This HTML tag <!-- COMMENTS --> is used to insert comments that won't be viewed by users into your pages. Some search engines read comment tags, which can include keyword text and descriptions. Comment tags are also used to hide javascript code from non-compliant browsers.

Concept Search - A search for documents related conceptually to a word, rather than specifically containing the word itself.

Content - Generally refers to the visible text on your Web page, links leaving your Web page, the text in relation to those links, etc.

Content Remixing - This process should be called Information Aggregation and ReDistribution along Secondary Vertical Channels.

Contextual Ad - Advertisements that are dynamically displayed based on the page content, e.g. laptop seller’s advertisements on a laptop blog.

Contextual Link Inventory - Text links that are shown depending on the content that appears around them. An extension of search engines where search engines placed targeted links on web sites that they deem to have similar audiences. (see also: CLI)

Conversion - Conversion refers to site traffic that follows through on the goal of the site (such as buying a product on-line, filling out a contact form, registering for a newsletter, etc.). Webmasters measure conversion to judge the effectiveness (and ROI) of PPC and other advertising campaigns. Effective conversion tracking requires the use of some scripting/cookies to track visitors actions within a website. Log file analysis is not sufficient for this purpose.

Conversion Optimization - Transforms your site into a selling tool - your site logically leads visitors through the sales cycle and closes sale.

Conversion Rate - This is the percentage of visitors to a site who actually take another action, like buying a product or filling out a survey. For example, if you collecting survey data, and 100 people visit your site, but only 17 people out of 100 complete the survey, you have a conversion rate of 17%.

Converting Search Phrase - A phrase that converts traffic into money.

COO - Abbreviation for Chief Operating Officer

Cookie - An information stored in special file on a user's computer by a web site so preferences are remembered on future requests. Also used for visit tracking purposes.

Co-op - Any exchange of links by a group this does not include direct person to person exchanges.

Copy - Text found on a web page.

Copywriter - A professional writer who specializes in the writing of advertising copy (compelling, engaging words promoting a particular product or service). See also SEO copywriter and web copywriter.

Cost Per Click - A marketing system of paying for targeted traffic. The cost or cost-equivalent that advertiser pays an agreed amount for each click someone makes on a link leading to they web site. (see also: CPC).

Cost per Thousand - The cost for each thousand impressions of your ad.

Cost-Per-Action - The online advertising payment model in which payment is based solely on qualifying actions such as sales or registrations. (see also: CPA)

Counters - Also called page counters. This is usually accompanied by something like "You are visitor number ___ ". Counters count page views, not visitors. The difference is that one visitor can generate numerous page views by opening many Web pages on the site. Counters are an inaccurate way to measure web site traffic and are generally considered amateurish by other visitors.

CPA - Abbreviation for Cost Per Action, the price paid for each visitor's actions from a paid search.

CPC - Abbreviation for Cost Per Click, the fee charged every time a user clicks on a banner ad or HTML link. It is the base unit of cost for a PPC campaign.

CPL - Cost Per Lead

CPM - Cost Per Thousand impressions. Marketing model where advertisers pays an agreed amount for the number of times their ad is seen by a consumer, regardless of the consumer's action. Heavily used in print, broadcasting and direct marketing, as well as with online advertisement sales. CPM stands for "cost per thousand," since ad views are often sold in blocks of 1,000. The M in CPM is Latin for thousand.

CPS - Abbreviation for Cost Per Sale.

Crawl, Crawling - Search Engine finds pages on the World Wide Web and records their details in its index by sending out programs called “spiders” or “robots”. These programs crawl they way from page to page and site to site by following text links.

Crawler - A BOT from a search engine that reads the text found on a website in order to determine what the website is about. Component of search engine that is gather listings by automatically crawling the web. A search engine's crawler, also called a spider or robot, follows links to web pages. It makes copies of the web pages found and stores these in the search engine's index.

CRM - Abbreviation for Customer Relationship Management

Cross Linking - Multiple websites or pages linking to each other.

CSS - Abbreviation for a standard layout language for the Web, one that controls colors, typography, and the size and placement of elements and images. CSS is intended by its creators “World Wide Web Consortium” (see also: W3C) to replace HTML table based layouts, frames, and other presentational hacks. Also file extension: filename.css

CSV - Abbreviation for Comma Separated Values

CTA - Abbreviation for Content Targeted Advertising. It refers to the placement of relevant PPC ads on content pages for non-search engine websites.

CTO - Abbreviation for Chief Technology Officer

CTR - Abbreviation for Click Through Rate. The value associated to the amount of times a paid ad is viewed. (see also: Click Through Rate)

CTR - Abbreviation for Click Through Ratio. (see also: Click Through Rate)

Customer Acquisition Cost - The cost associated with acquiring a new customer.

CVC | CVC2 - Abbreviation for Card Verification Code

CWO - Abbreviation for Chief Web Officer

CY - 2 Letter Language Code Welsh

Cybrarian - A person who finds, collects, and manages information available on the Internet.