Search engine marketing (SEM) is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) primarily through paid advertising. SEM may incorporate search engine optimization (SEO), which adjusts or rewrites website content and site architecture to achieve a higher ranking...

The concept behind Search Engine Marketing is quite simple: when a consumer or business person searches the Web through either a text box or by clicking through a directory hierarchy, he or she is in "hunt mode." This psychological state is unique because it signals to the search engine (and to...