- The first search engines were cataloging the early Web
- “Search engine optimization” came into use in 1997. Webmasters and content providers began optimizing sites for search engines
- All webmasters needed to do was 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
- Google was founded in 1998.
- Google attracted a loyal following among the growing number of Internet users, who liked its simple design.
- Off-page factors (such as Page Rank and hyperlink analysis) were considered as well as on-page factors (such as keyword frequency, meta tags, headings, links and site structure) to enable Google to avoid the kind of manipulation seen in search engines that only considered on-page factors for their rankings.
- By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation
- In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users
- In June 2007, The New York Times’ stated Google ranks sites using more than 200 different signals. The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages.
- In December 2009, Google announced it would be using the web search history of all its users in order to populate search results.
- Google Instant, real-time-search, was introduced in late 2010 in an attempt to make search results more timely and relevant. Historically site administrators have spent months or even years optimizing a website to increase search rankings.
- With the growth in popularity of social media sites and blogs the leading engines made changes to their algorithms to allow fresh content to rank quickly within the search results
Google announced the Panda update, which penalizes websites containing content duplicated from other websites and sources. Historically websites have copied content from one another and benefited in search engine rankings by engaging in this practice, however Google implemented a new system which punishes sites whose content is not unique.
In April 2012, Google launched the Google Penguin update the goal of which was to penalize websites that used manipulative techniques to improve their rankings on the search engine.
Google released the Google Hummingbird update, an algorithm change designed to improve Google’s natural language processing and semantic understanding of web pages.
Ps: If you are interested in SEO history, there’s a great online Sliders: http://www.slideshare.net/HubSpot/hub-spot-historyofseocoffeetips