Running a website may be, at times, if not most of the times, mind boggling. It may not show any conversion or, even if it shows, there is no sign of improvement. You are in deep analysis as to which content draws more views.
The A and B testing of Google Analytics is a very good tool in knowing how far you can go by letting you understand how far you have come. Through this tool, you may want to do the following activities, among others: letting your users make purchases, letting him sign-up for a newsletter, and improving your metrics like revenues and bounce rate.
A and B testing is a time tested analytical tool. It has been proven as sound and used in internet marketing professionally for years.