A crash course in startup metrics
tomblomfield.com
tomblomfield.com
[1] http://www.amazon.ca/The-Lean-Startup-Entrepreneurs-Continuo...
[2] http://en.wikipedia.org/wiki/Lean_Startup#Actionable_metrics
This book should be your bible. A lot of it is very similar to 4 Steps to the Epiphany, but Lean Startup is more approachable.
I'll edit the article to mention this book.
As a result they hit their quarterly revenue target (and got their quarterly bonuses) by amplifying their ad-spend to hundreds of thousands a month and buying customers for 110% of what they made from them.
This might seem like madness but when people's salaries and jobs depend on it, the line "what gets measured, gets done" is as true as true can be.
"Would you refer us to someone you know?" is often called "Net promoter score". You ask 100 of you customers if they'd recommend you to a friend [yes/no]. Subtract the latter from the former, and you get your score, from +100 to -100. Apple does consistently very well in these tests - around +70. The utilities firm I worked for hovered around -10.
You can use a more nuanced version with a score from 1-10. <=6 counts as -1, 7 or 8 is a zero, and 9 or 10 counts as +1.
This isn't really a measure of PR, though, because it surveys your existing customers.