Just because the ad didn't work, doesn't mean it's a bad ad. If the average person has a .001% chance of buying the Linux book and you have a .1% chance of buyi

Just because the ad didn't work, doesn't mean it's a bad ad. If the average person has a .001% chance of buying the Linux book and you have a .1% chance of buying it, the targeting improved the efficiency of the ad spend by 100x.