A few weeks ago, I searched for an email newsletter service that was based in Europe, preferably in Germany. I landed on a couple US-based sites and since then, I was retargeted by their ads all the time. But them being located in the States was a dealbreaker. All these ads never worked on me, because there was a specific reason I left the sites in the first place.<p>Leaving a site is a signal of disinterest, which is completely ignored. So, it would be interesting to take retargeting to the next level, by understanding why someone left the website and build up a bunch of triggers that would exclude some visitors.<p>E. g.: Person visits our blog, but leaves after that. Person reappears on another site of the same ad network that has keywords like "free", "open source" etc. in it -> strong signal that he doesn't want to pay -> remove from retargeting.