Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a web search engine‘s unpaid results — often referred to as “natural,” “organic,” or “earned” results


Getting indexed

The leading search engines, such as GoogleBing and Yahoo!, use crawlers to find pages for their algorithmic search results. Pages that are linked from other search engine indexed pages do not need to be submitted because they are found automatically. Two major directories, the Yahoo Directory and DMOZ, both require manual submission and human editorial review. Search engine crawlers may look at a number of different factors when crawling a site. Not every page is indexed by the search engines.

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. Additionally, a page can be explicitly excluded from a search engine’s database by using Meta tag specific to robots. When a search engine visits a site, the robots.txt located in the root directory is the first file crawled. Google warned webmasters that they should prevent indexing of internal search results because those pages are considered search spam.

Increasing Prominences

A variety of methods can increase the prominence of a webpage within the search results. Cross linking between pages of the same website to provide more links to important pages may improve its visibility.

Adding relevant keywords to a web page’s Meta data, including the title tag and Meta description, will tend to improve the relevancy of a site’s search listings, thus increasing traffic. URL normalization of web pages accessible via multiple URL’s, using the canonical link element or via 301 redirects can help make sure links to different versions of the URL all count towards the page’s link popularity score.

Types of SEO

There are mainly two types of SEO:

  • White Hat SEO: White hat SEO utilizes techniques and methods to improve the search engine rankings of a website which don’t run afoul of search engine (mainly Google) guidelines.
  •  Black Hat SEO: Black Hat SEO exploits weaknesses in the search engine algorithms to obtain high rankings for a website. Such techniques and methods are in direct conflict with search engine guidelines.