Search engines exist to help people find what they are looking for across the Internet.  Most search engines have two models: a paid advertising model and an unpaid organic model.

The paid model is Google Adwords where website owners create an advertisement, set up an advertising budget and then Google tries to match up the right (most relevant) advert with a web visitor’s search query.  The unpaid organic model relies on website that are naturally optimized for search engines, are easily indexed by search robots, and have a significant number of links pointing to them from other 3rd party websites that consider them to be a credible authority or subject matter expert (SME).

Timeline of a Google search