NY Times: Measuring Online Ad Effectiveness

MARKETERS have long said they would increase their online advertising budgets if Internet sites would do what they promised to do years ago: quantify the effects of an ad campaign on sales, brand awareness and other factors like the consumer’s intent to buy.
With each passing month, online companies are increasingly able to do just that. The question is, will marketers actually respond?(full story)

My spin: Online media is the ONLY media enabling advertisers to dynamically KNOW how their money is being spent and what affect their ads have on those seeing them.