In the pre-internet days of automotive marketing, the concept of a campaign was more universally understood. No one tried to measure the number of sales caused by a particular radio spot at 8:13 AM on station WKRP. It took multiple radio and TV spots working together to form a campaign. Each spot contributed to the campaign, and the campaign was measured for overall success. To some degree, the same concept applies across PPC, retargeting, and other online advertising. We can measure the success associated with a particular keyword far better than we ever could a particular radio spot, but the keyword modifications based on those results are an effort to optimize the overall campaign, and that’s a fact.