I am amazed by the amount of data that Google Analytics collects. You should put it in your own website, just to see the power of it -especially since so many business sites use something like this. Data is being collected on how many times you have been to the site, how long you stayed there, where you are from...and much more.
Do you already have a Google account and a website? You can log in and get started tracking your site.
You can learn more about it in this instructional video.