Search engines attempt to rank results for a given search based on their relevance to the topic, and the quality and reliability a site is judged to have. Google, the world’s most popular search engine, uses an ever-evolving algorithm that aims to evaluate sites in the way that a human reader would. This means that a key part of SEO involves ensuring that the website is a unique and relevant resource for readers.

To avoid undesirable content in the search indexes, webmasters can instruct spiders not to crawl certain files or directories through the standard robots.txt file in the root directory of the domain. Additionally, a page can be explicitly excluded from a search engine's database by using a meta tag specific to robots (usually ). When a search engine visits a site, the robots.txt located in the root directory is the first file crawled. The robots.txt file is then parsed and will instruct the robot as to which pages are not to be crawled. As a search engine crawler may keep a cached copy of this file, it may on occasion crawl pages a webmaster does not wish crawled. Pages typically prevented from being crawled include login specific pages such as shopping carts and user-specific content such as search results from internal searches. In March 2007, Google warned webmasters that they should prevent indexing of internal search results because those pages are considered search spam.[47]

Website owners recognized the value of a high ranking and visibility in search engine results,[6] creating an opportunity for both white hat and black hat SEO practitioners. According to industry analyst Danny Sullivan, the phrase "search engine optimization" probably came into use in 1997. Sullivan credits Bruce Clay as one of the first people to popularize the term.[7] On May 2, 2007,[8] Jason Gambert attempted to trademark the term SEO by convincing the Trademark Office in Arizona[9] that SEO is a "process" involving manipulation of keywords and not a "marketing service."


A content marketer, for example, can create a series of blog posts that serve to generate leads from a new ebook the business recently created. The company's social media marketer might then help promote these blog posts through paid and organic posts on the business's social media accounts. Perhaps the email marketer creates an email campaign to send those who download the ebook more information on the company. We'll talk more about these specific digital marketers in a minute.
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