There are two ways to track how much traffic your website gets.
The first way is through server-side statistics. Provided by your web host (some do not), it includes information on your site visitors.
The other way is through a remotely hosted website (such as our very own http://mapstats.blogflux.com/">MapStats). A remotely hosted program can give you more detailed information about your visitors, and it also discounts hits from automated-systems (and thus gives a more accurate traffic assessment).