How many times did you deploy a website and a client asked to see some visitor stats or maybe even conversion rates? At this point, many said sure, just go to Google Analytics; unfortunately, not every client wants to. Despite all Google's attempts to make their services user-friendly, many people are still reluctant to use them; may be because they have to create an account, or may be for some other reasons. At this point, I usually think how great it would be if I can bring Google Analytics to my back end? Fortunately for everyone Google offers Analytics API.
