Search engine optimization.

Definition: is the

Process of improving the volume or quality of traffic to a website from search engines via search result.
The examples of SEO are image search, local search and industry-specific verticalsearch engines. This gives a web site web presence. The best example is Google search where you can search any entity or object.
History.
Webmasters and content providers began optimizing sites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all a webmaster needed to do was submit the address of a page, or URL, to the various engines which would send a spider, extract links to other pages from it, and return information found on the page to be indexed.
Search engine optimization methods.
Getting indexed: The leading search engines, such as Google and Yahoo!, use to find pages for their algorithmic search results
Preventing crawling: To avoid undesirable content in the search indexes, webmasters can instruct spiders not to crawl certain files or directories through the standard robots.txt file in the root directory of the domain.

Increasing prominence: A variety of other methods are employed to get a webpage shown up in the searches results. These include 1)Cross linking.
2) Keyword Stuffing.
3) URL Normalization.
As a marketing strategy.
Eye tracking studies have shown that searchers scan a search results page from top to bottom and left to right, looking for a relevant result. Placement at or near the top of the rankings therefore increases the number of searchers who will visit a site. However, more search engine referrals does not guarantee more sales.

International markets.
Optimization techniques are highly tuned to the dominant search engines in the target market. The search engines market shares vary from market to market, as doe’s competition. As of 2009, there are only a few large markets where Google is not the leading search engine. In most cases, when Google is not leading in a given market, it is lagging behind a local player. The most notable markets were China and Japan.






List of Search Engines.
• 1 Geographical limited scope
• 2 Accountancy
• 3 Business
• 4 Enterprise
• 5 Mobile
• 6 News
• 7 People
• 8 Real property.

Relationship with search engines.
Search engines recognized that webmasters were making efforts to rank well in their search engines, and that some webmasters were even manipulating their rankings in search results by stuffing pages with excessive. Early search engines, such as Info seek adjusted their algorithms in an effort to prevent webmasters from manipulating rankings.
Due to the high marketing value of targeted search results, there is potential for an adversarial relationship between search engines and SEO. An annual conference, Adversarial Information Retrieval on the Web, was created to discuss and minimize the damaging effects of aggressive web content providers.
References .
1) Brian Pinkerton. "Finding What People Want: Experiences with the WebCrawler" (PDF). The Second International WWW Conference Chicago, USA, October 17–20, 1994. http://www.webir.org/resources/phd/pinkerton_2000.pdf.

2) Cory Doctored (August 26, 2001). "Metacarpi: Putting the torch to seven straw-men of the meta-utopia". E-Learning Guru. http://www.e-learningguru.com/articles/metacrap.htm.

3) Pringle, G., Allison, L., and Dower, D. (April 1998). "What is a tall poppy among web pages?”

4) Bring, Sergey and Page, Larry (1998). "The Anatomy of a Large-Scale Hyper textual Web Search Engine". Proceedings of the seventh international conference on World Wide Web.

5) Thompson, Bill (December 19, 2003). "Is Google good for you"? BBC News. http://news.bbc.co.uk/1/hi/technology/3334531.stm.
6) Sultan Gong and Hector Garcia-Molina (2005). "Link Spam Alliances" (PDF). Proceedings of the 31st VLDB Conference, Sondheim, Norway. http://infolab.stanford.edu/~zoltan/publications/gyongyi2005link.pdf.