As a marketing strategy for increasing a site's relevancy, SEO considers how search algorithms work and for what people search. SEO efforts may involve a sites presentation and structure, as well as fixing problems that could prevent search engine indexing programs from fully spidering a site. Other, more noticeable efforts may include ensuring that content is easily indexed by search engine robots and making the site more appealing to users.

The value of having your sites highly ranked and visible in search engine results, creates greater opportunity to reach more customers and possible sell more services.

The leading search engines, Google, Yahoo! and Microsoft, use crawlers to find pages for their algorithmic search results. Pages that are linked from other search engine indexed pages do not need to be submitted because they are found automatically. Some search engines, notably Yahoo!, operate a paid submission service that guarantee crawling for either a set fee or cost per click. Such programs usually guarantee inclusion in the database, but do not guarantee specific ranking within the search results.