Search engines have the main purpose to index thousands of millions of web pages. Once you look for a word or a phrase, the search engine scans automatically the entire database where it has the stored pages indexed and it returns to you as a result a list containing the most relevant results for that search.

The only criteria the number of pages found and their relevance depend on are the capabilities of the used search engine.

Search engines appeared somewhere in the early 90's when Alan Emtage, a student at the McGill University in Montreal created the first search engine like too. It was called Archie. Its purpose was to search through the information available on the FTP servers.

The files on these servers were available for anyone, but one could not use them unless knowing the exact address of the server and of the file. Archie looked through this database and gathered lists of files for each server. It was used by people to match phrases and characters in order to take them to the server address the file they were looking for was on.

Archie is now an old method, but its creation was the first step in the search engine rally that is going on now. As the public grew more and more aware of the existence of the internet, the need for a search tool became visible.

So, first there were some software robots, using the concept of spidering to index the web, following links from one site to the other and saving the text from all visited websites in a database.

Between 1994 and 1995 three important search engines appeared: Lycos, WebCrawler and AltaVista. At about the same time Yahoo! appeared but Yahoo! is not a search engine. Yes, it has a search engine function, but yahoo is firstly a director or data and articles, providing different services as email and hosting. Recently yahoo has signed contracts with other search engines as Google for both of them to provide more search results.

Today search engines are in a continuous competition. There are thousands of search engines, but just a few big ones. This small group of top search engines is responsible for more than 90% of online searches.

But the question arises: if search engines are free and they can be used by everyone what keeps them financially alive? The answer to the question is very simple: advertising and traffic. The more visits they have, the bigger the traffic then the more money they can make providing promotion space.

Search engines are competing to develop the best formulas and algorithms to evaluate the web pages accordingly to the keywords provided.