In 1990s Webmasters and content providers are starting optimizing sites for search engines. At that time search engines send "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed. Here is a question, What is search engine do?
The main focus of a search engine is to provide the information what anyone search in there page.
Then search engine process involves spider downloading a page and storing it on the search engine's own server, where a second program, known as an indexer at that time, extracts various information or data about the page, such as the words it contains and where these are located, as well as any weight for specific words, and all links the page contains, which are then placed into a scheduler for crawling at a later date.
After that site owners started to identify the value of having their sites extremely ranked to search engine and visible in search engine results, creating an chance for both white hat and black hat SEO specialists.
Sullivan credits Bruce Clay as being one of the first people to popularize the term SEO.
Webmasters starting the search algorithms and keyword. Then they know search engine start indexing files and using meta tags. What is meta tag? Meta tags provide a guide to each page's content.
By relying so much on factors such as keyword density which were exclusively within a webmaster's control, early search engines suffered from abuse and ranking manipulation. To provide better results to their users, search engines had to adapt to ensure their results pages showed the most relevant search results, rather than unrelated pages stuffed with numerous keywords by unscrupulous webmasters.
