Where Am I? - Internet Basics

The search engine uses web crawlers to look through web pages for any instance of the keyword or phrase you have entered.  They look at the headings, the URL and the text itself.  

The order of the search results returned by Google® is based primarily on an algorithm which assumes that the more times a web page has been linked to by other pages, the more important that page will be.  You will probably notice that Wikipedia entries are often one of the first search results returned.

Commercial and many non-commercial websites use a technique called search engine optimization (SEO) to improve their ranking in search results.  This involves tagging key words to their site address and to the content on their pages, which they anticipate you may use in your searches.  In this way, they can increase the chances that their site will turn up in your search. 

Some searches will bring the first few results as advertisements.  This is because the search engine is searching metadata or, data about data and has allowed paid ads to appear that match your search criteria.  For example if you search for the word telephone, the first few results in the search engine Bing show up as ads.  Some of the advertisements do not even have telephone in their title or web address but they have used the word as part of the metadata about their site.