This is called ad retargeting -- the basic premise being that conversion rates are much higher for items the user has actually looked at in the past. Usually it

This is called ad retargeting -- the basic premise being that conversion rates are much higher for items the user has actually looked at in the past. Usually it's only supposed to show abandoned purchases, but sometimes it doesn't work and shows you stuff you already bought. I personally feel retargeting to be a bit too intrusive for my tastes but the conversion numbers are excellent, which is why this industry has boomed in recent years. It looks like your browser's incognito mode can be useful for online gift shopping after all! There are a few companies who do this like Criteo or Adroll, but I believe Amazon is using Triggit [1]. It looks like it's working for them: http://marketingland.com/triggit-facebook-exchange-36-better-than-google-at-converting-retargeted-users-30462 http://marketingland.com/triggit-facebook-exchange-36-better... [1] http://blog.triggit.com/amazon-chooses-triggit%E2%80%99s-demand-side-platform-dsp-technology/ http://blog.triggit.com/amazon-chooses-triggit%E2%80%99s-dem...