CPM - is the cost per thousand for a particular site. A Web site that charges $15,000 per banner and guarantees 600,000 impressions has a CPM of $25 ($15,000 divided by 600).CPM is frequently used in advertising to represent cost per thousand (where M is the roman numeral of 1000). When used in advertising it relates to the cost per thousand page impressions.

CTA - Abbreviation for Content Targeted Advertising. It refers to the placement of relevant PPC ads on content pages for non-search engine websites. Content Targeted advertising is a form of advertising that uses the Internet and World Wide Web in order to deliver marketing messages and attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, advertising networks and e-mail marketing, including e-mail spam.

A major result of online advertising is information and content that is not limited by geography or time. The emerging area of interactive advertising presents fresh challenges for advertisers who have hitherto adopted an interruptive strategy.

CTR - Click Through Rate is a way of measuring the success of an online advertising campaign. A CTR is obtained by dividing the number of users who clicked on an ad on a web page by the number of times the ad was delivered (impressions). For example, if your banner ad was delivered 100 times (impressions delivered) and one person clicked on it (clicks recorded), then the resulting CTR would be 1 percent.

Banner ad click-through rates have fallen over time, often measuring significantly less than 1 percent. By selecting an appropriate advertising site with high affinity (e.g. a movie magazine for a movie advertisement), the same banner can achieve a substantially higher click-through rate. Personalized ads, unusual formats, and more obtrusive ads typically have higher click-through rates than standard banner ads.

Crawler - A program used by a search engine to "crawl" links on the Internet to find and index content. Also called a robot or spider. Can be used to identify and differentiate between types of crawlers indexing your site.

Creative - The technology used to create or develop an ad unit. The most common creative technology for banners is GIF or JPEG images. Other creative technologies include Java, - HTML, or streaming audio or video. These are commonly referred to as rich media banners.

Googlebot - The name of the spider used by Google. Instructions to Googlebot can be directed in the robots.txt file. Googlebot statistics can be viewed with web analytics software, on webserver logs, and in Google webmaster tools.

Keyword Audit - independent third-party verification of your keyword use, strategy, bidding, and return on investment.

Keyword Bidding - Keyword Bidding is the process or method used by search engines marketers to determine the ranking of paid keywords results in AOL, Google, MSN, Yahoo, and other search engines that require pay per click advertising to determine your ranking and positioning in their search results and in content results on networked partners' sites.

Keyword Research - Keyword research includes the processes and methodologies to research kewywords that would be used for search and internet marketing campaigns.

Link Popularity - A measure of inbound links. Several search engines have included this factor into their algorithms, the most notable being Goggle with their trademarked PageRank.

Listserver - A program that automatically sends email to a list of subscribers. It is the mechanism that is used to keep newsgroups informed.

Opt in/Opt out - An email marketing promotion that typically gives consumers an opportunity to "opt in" (taking action to be part of the promotion) or to "opt out" (taking action to not be part of the promotion). Marketers can be sensitive about the distinction, although many are secretly anxious about the day when email, like real-world direct mail, becomes an opt-out medium.