A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cache - Copy of a web page stored by a search engine. When you search the web you are not actively searching the whole web, but are searching files in the search engine index.
CGI - Common Gateway Interface - interface software between a web server and other machines or software running on that server. Many CGI programs are used to add interactivity to a web site.
Click Tracking - Counting the number of clicks that a link achieves through a counter program.
Cloaking - A spam trick generally used to get search engine positions. Different pages are displayed depending on the circumstances.
CMS - Content Management System. Tool used to help make it easy to update and add information to a website.
Co-citation - In topical authority based search algorithms links which appear near one another on a page may be deemed to be related to one another. In algorithms like latent semantic indexing words which appear near one another often are frequently deemed to be related.
Comments Tag - Some web developers also place comments in the source code of their work to help make it easy for people to understand the code.
HTML comments in the source code of a document appear as <!-- your comment here -->. They can be viewed if someone types views the source code of a document, but do not appear in the regular formatted HTML rendered version of a document.
Conceptual Links - Links which search engines attempt to understand beyond just the words in them. Some rather advanced search engines are attempting to find out the concept links versus just matching the words of the text to that specific word set. Some search algorithms may even look at co-citation and words near the link instead of just focusing on anchor text.
Concept Search - A search which attempts to conceptually match results with the query, not necessarily with those words, rather their concept.
Contextual Advertising - Advertising programs which generate relevant advertisements based on the content of a webpage.
Cookie - Small data file written to a user's local machine to track them. Cookies are used to help websites customize your user experience and help affiliate program managers track conversions.
CPA (Cost Per Action) - Cost per action. The effectiveness of many other forms of online advertising have their effectiveness measured on a cost per action basis. Many affiliate marketing programs and contextual ads are structured on a cost per action basis. An action may be anything from an ad click, to filling out a lead form, to buying a product.
CPC (Cost Per Click) - Cost per click. Many search ads and contextually targeted ads are sold in auctions where the advertiser is charged a certain price per click.
CPM (Cost per thousand ad impressions) - Many people use CPM as a measure of how profitable a website is or has the potential of becoming.
Crawler - A Spider that downloads multiple pages from the same domain.
Crawling - The spider that look for links in the pages (urls) it downloads and then crawl down through the domain.
Crawl Depth - How deeply a website is crawled and indexed.
Crawl Frequency - How frequently a website is crawled. Sites which are well trusted or frequently updated may be crawled more frequently than sites with low trust scores and limited link authority.
Cross Linking - The inner linking among a group of domains those are owned by a single individual. This is often done for increasing link popularity.
CSS (Cascading Style Sheets) - Cascading Style Sheets is a method for adding styles to web documents. Using external CSS files makes it easy to change the design of many pages by editing a single file.
CTR (Click Through Rate) - Clickthrough rate - the percentage of people who view click on an advertisement they viewed, which is a way to measure how relevant a traffic source or keyword is. Search ads typically have a higher clickthrough rate than traditional banner ads due to being highly relevant to implied searcher demand.
Cybersquatting - Registering domains related to other trademarks or brands in an attempt to cash in on the value created by said trademark or brand.