Search Engine Optimization

Search Engines

One official definition of a search engine is that it is a tool that enables users to locate information on the World Wide Web.
Search engines allows someone to ask for content meeting specific criteria (typically those containing a given word or phrase) and retrieves a list of items that match those criteria. This list is often sorted with respect to some measure of relevance of the results.

There are basically three types of search engines: human indexed (a.k.a. directories), spider (a.k.a. robots or crawlers) indexed and those that are a combination of the two. Without search engines it would be basically impossible to find anything on the internet without knowing the specific URL address.

Search engines are a major part of the internet. Most internet traffic (around 80%)is generated through the use of search engines.

Search engines use spider software which combs the internet looking for documents and web addresses. The documents and web addresses are collected, indexed and stored in a database. Different search engines index different information. Some index all the content in a web page, some index the content and meta tags, while others only index the title.

When a search engine user enters words to be searched, the database looks for words that match. The search engine then generates results with links. So in effect, you're not really searching the web, you are searching through the database of indexed pages that the spider/crawler/robot has found previously.