In mid 1990s, search engines began listing the websites which were submitted by the webmasters. The search engines would run the spiders and collects data. These websites were then categorized according to the information in the websites. The webmasters realizing the significance of these search engines started optimizing the websites and the terminology search engine optimization was born.
It was believed that meta tags influenced the position of website and brought focused traffic to the relevant web pages. Some web master started abusing meta tags by adding too many meta tags and writing irrelevant keywords. This illegitimate use of meta tags made the website to rank in search that was not related with their business. In early 2000s, the search engine started following stricter and complex method of ranking the websites. Websites having inappropriate keywords or over use of keywords were pulled down from the ranking.
The Google search engine started the concept of PageRank. The PageRank algorithm was based on the link popularity. The incoming links to a website is interpreted as a vote. Webmasters started exchanging links with other websites. Google found that some of the websites bought and sold links to other websites that were not useful to the internet user visiting their website. This made Google to follow more complex process of PageRank to list the optimized websites.
Google started keeping secret algorithm in ranking the websites. Google updates its index of websites which causes frequent shifts in page ranking and this came to be known as Google dance.
