Someone asked me yesterday about tracking site visitors and how to do it.  I’ve long been a proponent of using more than one analytics program, because what one misses the other may catch.  Knowing a lot of information about visitors can be very helpful.  I recommend at least using a statistics program provided by your host for free (and any good host provides this service in their control panel now) and Google Analytics.  That will give you a pretty good idea of what’s going on.