Cost per click (CPC) is a method of charging advertisers for the user clicks their advertisements have received.
Cost per click is the going method for charging for targeted advertising, such as search ads, while cost per impression (CPM) is largely associated to branding advertisements, such as banner ads. Cost per acquisition (CPA) charges only for users who have committed a transaction or conversion.
The conversation between browsers and servers takes place according to the hypertext transfer protocol, or HTTP.
Written by Tim Berners-Lee, it was first implemented on the web in 1991 as HTTP 0.9. Currently, web browsers and servers support version 1.1 of HTTP. It supports persistent connections, meaning that once a browser connects to a web server, it can receive multiple files through the same connection.
Reach is the number of different types of individuals that see an ad or message. Reach also applies to how well-known particular sites or groups of sites are. Web research and reporting companies like RelevantKnowledge issue monthly reports on the 25 sites with the greatest overall reach, as well as more detailed reports on demographic characteristics by site.
Validation is a way to make sure that your code is compliant with the current HTML specifications. This means you can check to make sure that you didn’t accidentally use proprietary tags that would only work on your particular browser. There are many HTML validation sites on the Web, such as Bobby, which will analyze single web pages for their accessibility to people with disabilities, Weblint, one of the first validators, and the World Wide Web Consortium’s rigorous validator, which provides validation for HTML 4.0.