I use Google Analytics to specially for,
# Check adsense earnings, CPM, CTR
# Time on each hub & Bounce rate
# Country & City of users
I use above factors in my future writing, those stats helps me to find best topics. For an example, I started with writing about Sri Lankan Celebrities, but later I found those hubs are even famous among South Indian fans by Analytics. Then I moved to South Indian celebrites. Also I found most of my hubs are famous among UK, USA & Philiphines. So I decided to write hubs which suited for those countries.
Sometime I change the layout of hubs when it is not performing well. So after any big change I done, I used to check the performance by using Analytics. Sometime it doesnot working, but Analytics helps me to find it. Performance means traffic, adsense revenue.
It also help me to improve existing hubs which has higher bounce rate. I always link each hub to others, but location of those links are not suitable then I change the location of links to reduce my bounce rate. I hope those things definetly help you as well. I highly recommend anyone to use Google Analytics if he or she want to earn more $$$$.
I hope these clarification helps you to clear your quiz. If you need any help Im happy to help you.