Ever wonder how your browser got smart enough to take you to a page even when you leave the prefix www out of the equation? It has less to do with the browser and more to do with A-records. These are settings that are configured in your hosting or domain registration service such as GoDaddy.com. When you type a naked domain such as example.com into a browser instead of www.example.com, you are linked to another IP address for which there is a record. If no such record exists, the user gets an error message. If you are using GoDaddy.com or some other domain registration service user will be directed to a page generated by that service. Either way, users are not seeing your site.
Most people, myself included, feel it second nature to just type a naked domain into a browser and expect to get the site we are thinking of. Should it not appear it is not a stretch to say that most people will resort to using a search engine before typing in www to get the result they want.