Cache - A cached page is a copy of a page that is stored locally (in our case on a search engine database). On most search engines the cached pages are not visible to users; however Google let everyone see their cached version of a certain website.
Clickthrough rate (CTR) – Clickthrough rate (CTR) represents the percent of people that clicked on a link (generally an advertising link); for example if a banner ad is viewed by 100 people and 6 of them clicked on it than it means that this banner ad has a clickthrough rate (CTR) of 0,06 or 6%.
Cloaking – Cloaking is a black hat SEO tactic that use a script to deliver different content for the same page to search engine spiders and human visitors. It was one of the most efficient black hat SEO tactics in the past, but it has no real effect nowadays.
Conversion – Conversion is the act of converting a visitor into a customer or a member of a site. For a certain site there may be different level of conversions (for example the number of customers that become free members and the number of customers that become paid members).
Conversion rate – Conversion rate represents the percent of people that are converted to customers; again for a certain site there may be different level of conversions (for example the number of customers that become free members and the number of customers that become paid members). For example if a site has 100 visitors from which 10 become free members and 5 other become paid members we can say that the site had a 0,10 or 10% conversion rate for free members, 0,05 or 5% conversion rate for paid members and 0,15 or 15% conversion rate for members as a whole.
Cost Per Action (CPA) – Cost per Action (CPA) is a way of paying for advertising services where the advertisers pay only once a certain action was completed by a visitor that come from a certain advertisement (for example becoming a member of that site or making an order).
Cost Per Click (CPC) – Cost per Click (CPC) is a way of paying for advertising services where the advertisers pay only a visitor comes from a certain advertisement. It is the most popular advertising payment solution nowadays, being used by Google Adwords and Yahoo Search Marketing.
Cost Per Thousand (CPM) - Cost per Thousand (CPM) is a way of paying for advertising services where the advertisers pay every time someone sees the advertisement. The Counter– A counter is a tool / program that tracks the number of visitors of a web page.
Crawler (web crawler) – A crawler is a program that is used by a search engine to automatically explore the web and download, analyze and save the content of any page it finds. It is also called bot, robot, or spider.
Cascading Style Sheet (CSS) - Cascading Style Sheet (CSS) is a programming language used to control the look of a web page.
Custom error pages – Customer error pages are used to replace the browser default error page with a custom page that not only let the user know that there is an error with the page he was trying to access but also offer him navigation alternatives within the site. It is used to keep the visitors on the site in case they come to a page that does not exist anymore (404 error) or a page that can’t be displayed properly.
