Search engine optimization

Search engine optimization (SEO) is the process of improving the quality and quantity of website traffic to a website or a web page from search engines. SEO targets unpaid search traffic (usually referred to as "organic" results) rather than direct traffic, referral traffic, social media traffic, or paid traffic.

Organic search engine traffic originates from a variety of searches, including image search, video search, academic search, news search, industry-specific vertical search engines, and large language models.

As an Internet marketing strategy, SEO considers how search engines work, the algorithms that dictate search engine results, what people search for, the actual search queries or keywords typed into search engines, and which search engines are preferred by a target audience. SEO helps websites attract more visitors from a search engine and rank higher within a search engine results page (SERP), aiming to either convert the visitors or build brand awareness.

Webmasters and content providers began optimizing websites for search engines in the mid-1990s as the first search engines were cataloging the early Web. Search engine users would query the URL of a page, and then receive information found on the page, if it existed in the search engine's index.

ALIWEB and the earliest versions of search engines required website developers to manually upload website index files in order to be searchable and widely did not utilize any form of ranking algorithm for user queries. The emergence of automated web crawlers would later be used to proactively discover and index websites. This led to website developers to optimize their website’s search signals, including the use of meta tags, to achieve greater visibility in search results.

According to a 2004 article by former industry analyst and current Google employee Danny Sullivan, the phrase "search engine optimization" came into use in 1997. Sullivan credits SEO practitioner Bruce Clay as one of the first people to popularize the term.

In some cases, early search algorithms weighted particular HTML attributes in ways that could be leveraged by web content providers to manipulate their search rankings. As early as 1997, search engine providers began adjusting their algorithms to prevent these actions. Eventually, search engines would incorporate more meaningful measures of page purpose, including the more recent development of semantic search.

Some search engines frequently sponsor SEO conferences, webchats, and seminars. Major search engines provide information and guidelines to help with website optimization. Google has a Sitemaps program to help webmasters learn if Google is having any problems indexing their website and also provides data on Google traffic to the website. Bing Webmaster Tools provides a way for webmasters to submit a sitemap and web feeds, allows users to determine the "crawl rate", and track the web pages index status.