Search engines have the chief purpose to index 1000s of 1000000s of web pages. Once you search 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 outcomes for that search.
Search engines came along someplace in the early 90’s when Alan Emtage, a student at the McGill University in Montreal produced the first search engine like tool. It was named Archie. Its purpose was to search through the data available on the FTP servers. The files on these servers were available for anybody, but one couldn’t utilize them unless knowing the exact address of the server and of the file. Archie looked through this database and amassed lists of files for each server. It was utilized by individuals to match phrases and characters in order to take them to the server address the file they were seeking was on.
Archie is today an old technique, but its creation was the first step in the search engine rally that's going on today. As the public grew more and more aware of the existence of the Net, the need for a search tool became obvious.
So, first there were a few software robots, using the concept of spidering to index the web, following links from one web site to the other and saving the text from all visited sites in a database.
Between 1994 and 1995 3 crucial search engines appeared: Lycos, WebCrawler and AltaVista. At about the same time Yahoo! appeared but Yahoo! Isn't a search engine. Yes, it has a search engine routine, but yahoo is firstly a director or data and articles, supplying different services as email and hosting.
Nowadays search engines are in a ceaseless competition. There are 1000s of search engines, but just a couple of big ones. This small group of top search engines is responsible for more than 90% of net searches.
But the query arises: if search engines are free and they can be utilized by everybody what keeps them financially alive? The answer to the question is really easy: advertising and traffic. The more visits they have, the greater the traffic then the more money they may make providing promotion space.
Search engines are competing to evolve the best formulas and algorithms to evaluate the web pages accordingly to the keywords supplied.
If somebody is seeking a top position in search engines, then he has to be sure that his site is projected in such a way that search engines would discover it easily, being relevant for the keywords and phrases the owner wishes it to be found by.