Acronym for Cost Per Acquisition (sometimes called Cost Per Action), which is the total cost of an ad campaign divided by the number of conversions. For example, if a campaign cost $100 and resulted in 5 conversions, the CPA is $20 ($100 / 5). It cost $20 to generate one conversion.

Acronym for Cost Per Click, or the amount search engines charge advertisers for every click that sends a searcher to the advertiser’s web site. For an advertiser, CPC is the total cost for each click-through received when its ad is clicked on.

Acronym for Cost Per Thousand Impressions (ad serves or potential viewers). Compare to CPC pricing (defined above). CPM is a standard monetization model for offline display ad space, as well as for some context-based networks serving online search ads to, for example, web publishers and sites.

Computer robot programs, referred to sometimes as "crawlers" or "knowledge-bots" or "knowbots" that are used by search engines to roam the World Wide Web via the Internet, visit sites and databases, and keep the search engine database of web pages up to date. They obtain new pages, update known pages, and delete obsolete ones. Their findings are then integrated into the "home" database. Most large search engines operate several robots all the time. Even so, the Web is so enormous that it can take six months for spiders to cover it, resulting in a certain degree of "out-of-datedness" (link rot) in all the search engines.

Short for customer relationship management. CRM entails all aspects of interaction a company has with its customer, whether it be sales or service related. Computerization has changed the way companies are approaching their CRM strategies because it has also changed consumer buying behavior. With each new advance in technology, especially the proliferation of self-service channels like the Web and WAP phones, more of the relationship is being managed electronically. Organizations are therefore looking for ways to personalize online experiences (a process also referred to as mass customization) through tools such as help-desk software, e-mail organizers and Web development apps.

Cascading Style Sheets - An addition to your HTML, a web site`s "cascading style sheet" contains information on paragraph layout, font sizes, colors, etc. A cascading style sheet has many uses as far as search engine optimization and web site design are concerned.