Retargeting ads work by checking to see a product you’ve looked at and then showing you that product over and over again with the hope that at some point you buy it. There are entire companies dedicated to this with extremely sophisticated algorithms so I’m surprised when I see inefficient behavior. In my case it was an Amazon ad that kept following me around even after I already purchased the product, a precision cooker. Given that Amazon knows my purchase history and sees that I’ve already bought the cooker it makes no sense to keep showing it to me. It seems that their algorithm figured this out as well and started showing me the same product in different packages and at different price points. The fact that they have logic that’s smart enough to show me different variations of the same product but not take into account my purchase history shocks me. What makes this even worse is that I own some Amazon stock and realize that this inefficiency has an impact, albeit a tiny one, on my shares.