SEO – Scope and Methodology
SEO has matured with time and its algorithms and hence its definitions have changed enormously in order to cope up with the changing requirements. There are no standard algorithms followed by all search engines. Every search engine has defined their own algorithms to rank pages as well as position pages prior to a search on certain keyword. Lack of standard algorithms has made this task very difficult, as there are no definite ways with which one can achieve this. No search engine discloses their search engine algorithms. However, many practices have been devised based upon continuous research and after monitoring the behavior of search engines to certain keywords.
Every search engine has its own unique criteria for determining the type of pages they consider the most "relevant" for a given search. Therefore, a page that ranks well in one engine may rank poorly in another. Few search engines may like to see META tags, other may not. Some search engines look for keywords in the ALT tag of a graphic image, and others do not.
Search engines could be broadly classified as:
- Directory Engines: Sometimes referred to as catalogs, these are the engines that manage their own directory of categorized websites. The content of the major directories are often licensed and used by other search engines. Therefore, inclusion in one directory can get listed among different search engines.
- Crawler Based Search Engines: As the web is growing, it has become almost impossible to manage indexing of large number of sites by human reviewers. However, Crawlers are the solution to these. These are the intelligently programmed robots (or crawlers) that visit a site and index the site according to its contents.
- Hybrid Search Engines: Most engines fall into the general "search engine" category. They often combine crawler-based search results with a human reviewed directory of Web sites. These search engines rank page at least in part by the content of the page. Some people call these engines "hybrids" since they combine technologies from both directory and crawler-based engines.
- Pay per Click: Instead of ranking pages by their actual content, these engines will rank sites based on who pays the most per click to be listed for the keyword being searched. You can place bids for top positions on these sites in an auction-like environment. Top positions can sometimes be secured for as little as one cent per click (i.e., visitor to your site). Many major search engines include several Pay per Click listings in a "Sponsored" or "Featured" portion of their search results.