In many ways, digital marketing (any form of it, from PPC to SEO) is just like starting and managing a start up.
In our article about Display Performance 101: Conversions and Conversion Rates Laura wrote about why with the proper metrics and using conversion tracking, you can easily learn how your ads are performing and where you need to invest more. And she mentioned something about tracking code.
The trick question for anyone running ad campaigns: How do you measure performance? What do you look at when you need to decide if a campaign or an ad is performing or underperforming?