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) through optimization and advertising. SEM may use search engine optimization (SEO), which adjusts or rewrites website content to achieve a higher ranking in search engine results pages or use pay per click listings.
In 2012, North American advertisers spent $19.5 billion on search engine marketing. The largest SEM vendors were Google AdWords and Bing Ads. As of 2006, SEM was growing much faster than traditional advertising and even other channels of online marketing. Because of the complex technology, a secondary 'search marketing agency' market has evolved. Some marketers have difficulty understanding the intricacies of search engine marketing and choose to rely on third party agencies to manage their search marketing.
As the number of sites on the Web increased in the mid-to-late 90s, search engines started appearing to help people find information quickly. Search engines developed business models to finance their services, such as pay per click programs. Google began to offer advertisements on search results pages in 2000 through the Google AdWords program. By 2007, pay-per-click programs proved to be primary money-makers for search engines. In a market dominated by Google, in 2009 Yahoo! and Microsoft announced the intention to forge an alliance. The Yahoo! & Microsoft Search Alliance eventually received approval from regulators in the US and Europe in February 2010.
Methods & Metrics
There are 3 categories of methods and metrics used to optimize websites through search engine marketing.
1. Keyword Research and Analysis involves three "steps": ensuring the site can be indexed in the search engines, finding the most relevant and popular keywords for the site and its products, and using those keywords on the site in a way that will generate and convert traffic.
2. Website Saturation and Popularity, or how much presence a website has on search engines, can be analyzed through the number of pages of the site that are indexed on search engines (saturation) and how many backlinks the site has (popularity). It requires pages to contain keywords people are looking for and ensure that they rank high enough in search engine rankings.
3. Back-End Tools, including Web analytic tools and HTML validators, provide data on a website and its visitors and allow the success of a website to be measured. They range from simple traffic counters to tools that work with log files and to more sophisticated tools that are based on page tagging.
Comparison with SEO
SEM is the wider discipline that incorporates SEO. SEM includes both paid search results (Google Adwords) and organic search results (SEO). SEM uses paid advertising with AdWords or Bing Ads, pay per click (particularly beneficial for local companies as it enables potential consumers to contact a company directly with one click), article writing & advertising. SEM and SEO both need to be monitored and updated frequently to reflect evolving best practices. In some contexts, the term SEM is used exclusively to mean pay per click advertising, particularly in the commercial advertising and marketing communities which have a vested interest in this narrow definition. Such usage excludes the wider search marketing community that is engaged in other forms of SEM such as search engine optimization and search retargeting.