Many sites do not make money. Those who want only a web site, usually have just an web site.
Google defines search engine : "a program that searches for and identifies items in a database that correspond to keywords or characters specified by the user, used especially for finding particular sites on the World Wide Web".
A good definitions is given by google: "Search engines use automated software (known as robots or spiders) to follow links on Websites, harvesting information as they go. When someone submits a query to a search engine, the engine returns a list of sites, ranking them on their relevance to the keywords used in the search."
They also affirm that "The journey of a query starts before you ever type a search, with crawling and indexing the web of trillions of documents".
In short, search engines use crawlers, which is applications that gather information on the internet pages. Then the information is classified and indexed.
After the discovery and analysis pages, follows a process of indexing these pages. This index is relavant for us, because this index is what the search engines gives us when we use.
Suppose we want to buy a tablet and type it in the search engines.
Note that the results are different and some not directly related to what actually interested.About this, we have no direct connection with the subject we will discuss in the following materials.
So search engines gives us an index of information they hold. The fact that this information is relavant for us or not is something that search engines are unable to determine with accuracy.
That's what search engines do.
How and if they succeed we will discuss this in the following articles.