Most site hosting vendors provide site statistics information. This usually includes information about the number of unique site visitors, which pages were accessed, what browsers were used and something about the types of workstations and O/S used to access the site.
This kind of information allows you to judge the effectiveness of your web site marketing, and to fine tune the site to more closely match the workstation setups most used by your visitor base.
It is invaluable information for your webmaster and site marketer, and you should insure that any site hosting plan you purchase includes access to at least basic site statistics.