You may want to know who has been visiting your site - what pages they looked at, how long they stayed there, what country they are from etc, etc. It all helps you to see what you are getting from your website and what your future strategy should be.
Google Analytics is the enterprise class website analytics solution that gives you rich insights into your website traffic and internet marketing effectiveness. Powerful, flexible and easy-to-use features let you see and analyse your website traffic data in an entirely new way. With Google Analytics, you're more prepared to write better targeted ads, strengthen your marketing initiatives and create a more productive website.