Instead of thinking of the difference between targeted and untargeted advertising as a shotgun vs. sniper rifle type of situation, you should think of it as a sawn-off shotgun vs. regular shotgun type of deal.<p>Targeted advertising does in fact work. I know this because I work for an ad company, and it is very clear in both click- and conversion-rates.<p>The product specific level of targeting you are talking about, might be feasible for amazon... might be. But it isn&#x27;t for our company since it is relatively difficult to maintain the segmentation and targeting rules required for it to work. The ROI is simply too low.<p>There are lots of other easier targeting options with a proven effect such as, frequency, geo, audience segmentation, site&#x2F;product segmentation (such as the retargeting campaigns you have probably experienced), predictive behavioral targeting, and so on.<p>We typically see 1.2 to 2 times as many clicks on campaigns using a mix of the mentioned targeting options above, compared to campaigns with no targeting.