Starting with the WHY, we explore Optimised CPM  
- We also cover HOW this works, and why this means that the VALUE classic metrics like CPC, CTR and yes, even CPM... have been completely undermined.  

Optimized CPM (Cost per 1,000 impressions) is a bid type that shows your ad to people who are more likely to take the action you want. For example, if your advertising objective is to drive customers to your website, an optimized CPM bid will be shown to people who are more likely to navigate to your external link.  With this bid type, you pay for impressions (CPM). Your bid will automatically adjust to help your ads reach the people you care about, but you won't spend more than your budget.