Search engine optimization or SEM as it is often called, is an important facet of Search Engine Marketing, which aims to promote and increase traffic to websites. Search engine marketing is also known as SEM because it involves the online promotion of sites through paid advertisements on search engines, primarily through pay-per-click advertising. The SEM process includes many different processes that are designed to increase the rankings of sites in search results for specific key phrases, key demographics, geographic regions, and other factors. In recent years, Pay Per Click has become one of the most popular ways of driving traffic to websites, due to the relatively low cost per click and the high number of potential customers it can reach.