Advertisers would know exactly how many people viewed each ad, and whether they had been intrigued enough to click on it in order to buy the item or sign up for the service. All would be measurable, quantifiable, exact. In a sense, it worked too well.
Advertisers do know how many people are clicking on their ads.
It turns out to be very few. Unfortunately, we shot ourselves in the foot. It's not only Web surfers who are losing interest. Internet start-up companies, which have bought the bulk of online ads, are increasingly selective about where they put their dwindling dollars. Meanwhile, the major off-line brands aren't promoting their wares on the Internet quite as much as expected.