Conversion Funnel - Impressions, Clicks, Sales, Revenue Share

Digital marketing is highly measurable. Unfortunately, still too many advertisers do not track through to "conversions." Even packaged goods, soda, and entertainment advertisers that do not sell products online can track "conversion events" that are indicative of the lift in sales in offline channels -- e.g. the number of click-and-print coupons that are then taken to the grocery store for redemption. 

See: May The Ratio Be With You

Furthermore, the extreme detail with which digital marketing programs can be tracked should differentiate it from traditional advertising channels which try to get a single message to as many people as possible. 

The conversion ratios that I have tracked for 8 years continuously reveal that in some cases, the economics of digital marketing actually do not work. For example, it might take 10,000 display ad impressions to generate 100 clicks (1% click through rate); then there might be 1 purchase (1% conversion rate). If the profit margin on the purchase is less than the media cost of the 10,000 ad impressions, the economics simply don't work. 

Also see Digital Advertising Benchmarks