1990 Archie implementation was written, a tool for indexing FTP archives

late spring of 1991 Gopher system was released

1992 Veronica is a search engine system for the Gopher protocol, developed by Steven Foster and Fred Barrie at the University of Nevada, Reno.

In January 1994, Jerry Yang and David Filo were electrical engineering graduate students at Stanford University when they created a website named "David and Jerry's Guide to the World Wide Web" In April 1994, "David and Jerry's Guide to the World Wide Web" was renamed "Yahoo!". The yahoo.com domain was created on January 18, 1995.

1995 Webmasters and content providers began optimizing sites for search engines.  Initially, all webmasters needed to do was submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page.

15 December 1995 AltaVista was created by researchers at Digital Equipment Corporation's Western Research Laboratory who were trying to provide services to make finding files on the public network easier. Traffic increased steadily from 300,000 hits on the first day to more than 80 million hits a day two years later.

1997  phrase "search engine optimization" probably came into use 

1997 August The first documented use of the term Search Engine Optimization was John Audette and his company Multimedia Marketing Group as documented by a web page from the MMG site from August, 1997 on the Internet Way Back machine (Document Number 19970801004204). The first registered USA Copyright of a website containing that phrase is by Bruce Clay effective March, 1997 (Document Registration Number TX0005001745, US Library of Congress Copyright Office).

Graduate students at Stanford University, Larry Page and Sergey Brin, developed "backrub,"PageRank, is a function of the quantity and strength of inbound links. PageRank estimates the likelihood that a given page will be reached by a web user who randomly surfs the web, and follows links from one page to another. In effect, this means that some links are stronger than others, as a higher PageRank page is more likely to be reached by the random surfer.

1998 Page and Brin founded Google Google attracted a loyal following among the growing number of Internet users, who liked its simple design.

In 2000, Yahoo! began using Google for search results

3 January 2000 Yahoo! stocks closing at an all-time high of $118.75 a share

26 September 2001 $4.05

February 2003, AltaVista was bought by Overture Services, Inc. In July 2003, Overture itself was taken over by Yahoo!.

By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation. Google says it ranks sites using more than 200 different signals.^[11] The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages.

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 2007 Google announced a campaign against paid links that transfer PageRank. 

June 15, 2009, Google disclosed that they had taken measures to mitigate the effects of PageRank sculpting by use of the nofollow attribute on links. Matt Cutts, a well-known software engineer at Google, announced that Google Bot would no longer treat nofollowed links in the same way, in order to prevent SEO service providers from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEO engineers developed alternative techniques that replace nofollowed tags with obfuscated Javascript and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and Javascript. 

2008, Bruce Clay said that "ranking is dead" because of personalized search. It would become meaningless to discuss how a website ranked, because its rank would potentially be different for each user and each search.^[16]

In December 2009 Google announced it would be using the web search history of all its users in order to populate search results.

late 2009 Real-time-search was introduced. 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.

September 2010, Veronica-2 is a complete rewrite of Veronica by Cameron Kaiser its index contained 1,320,747 selectors.

December 2010, a Yahoo employee leaked PowerPoint slides that the search engine Alta Vista would be shut down as part of a consolidation at Yahoo.

24 February 2011 Panda 1.0: Launched about 12% of the rankings in the United States changed. 

11 April 2011 Panda 2.0: Launched. This incorporated Google “blocking” data and affected about 2% of searches in the US. It also saw the algorithm roll out globally. 

White Hat Marketing

White hat marketing applies the White hat SEO techniques, also known as ethical SEO. The white hat marketing implies that all SEO activities are carried out while conforming to the guidelines, rules and policies of search engines. It is an ethical guideline since all site managers abide to the written, as well as unwritten rules and guidelines for SEO. Some of these guidelines are:

• Providing relevant keywords that cater for short and long tails results
• Updating the content regularly
• Analysing search results analytics reports and take corrective actions as required
• Providing links to other websites as well as requesting other networks to link to this website

Black Hat Marketing

Black hat marketing involves SEO activities that are against the norms of search engines. Hence, black hat marketing is unethical. It is difficult for the search engine alone to distinguish when black hat SEO is applied. Competitors can play a role by reporting cases of black hat marketing to the search engines, who will in turn ban or penalise the website. Despite the risk of ban, marketers still can go for black hat marketing because it helps in boosting up the page location in search result. Example of Black hat marketing are:

• keyword stuffing - keywords can be provided, among others, in meta tags,alt tags, comment tags, as invisible text to human eyes. By overusing the same keywords throughout a web page, search engines algorithm, that reads keywords, will drive the web page up in its search result.
• doorway and cloaked pages - web site contain web pages that are listed in search result. However, when entering these pages, users are redirected to other pages. Hence, the search result contents do not match the page displayed to users.
• link farming
• Hidden text - Hiding text in the page or website is also considered as black hat seo technique. This technique is considered as spam and search engine can ban the website.