Many analytics software packages such as WebTrend and SiteCatalyst cost money.  Google provides their analytic software for free.  With Google Analytics you can measure traffic for your website.  Google provides many options.  With Google Analytics you can see how many times your website was accessed,how many pages were visited, how long the visitors stayed on your site, how many unique visitors came to the site, what devices or browsers did they use to access the site, what keywords they used to get to the site and a zillion more things!