Another way search engine marketing is managed is by contextual advertising. Here marketers place ads on other sites or portals that carry information relevant to their products so that the ads jump into the circle of vision of browsers who are seeking information from those sites. A successful SEM plan is the approach to capture the relationships amongst information searchers, businesses, and search engines. Search engines were not important to some industries in the past, but over the past years the use of search engines for accessing information has become vital to increase business opportunities. The use of SEM strategic tools for businesses such as tourism can attract potential consumers to view their products, but it could also pose various challenges. These challenges could be the competition that companies face amongst their industry and other sources of information that could draw the attention of online consumers. To assist the combat of challenges, the main objective for businesses applying SEM is to improve and maintain their ranking as high as possible on SERPs so that they can gain visibility. Therefore, search engines are adjusting and developing algorithms and the shifting criteria by which web pages are ranked sequentially to combat against search engine misuse and spamming, and to supply the most relevant information to searchers. This could enhance the relationship amongst information searchers, businesses, and search engines by understanding the strategies of marketing to attract business.
Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters only needed to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed. The process involves a search engine spider downloading a page and storing it on the search engine's own server. A second program, known as an indexer, extracts information about the page, such as the words it contains, where they are located, and any weight for specific words, as well as all links the page contains. All of this information is then placed into a scheduler for crawling at a later date.