There is no way I could sum up this story better than AdFreak writer David Griner. So, in the absence of blog muses, I'm just going to copy and paste exactly what he wrote.
Nowhere on David Berkowitz's Facebook profile did it say he was Jewish. So, he was a bit surprised to see a targeted travel ad with the headline "Hey Jew." While Berkowitz, an interactive marketing specialist and blogger, is indeed Jewish, he wondered how the advertisement figured it out. Was it based on his hometown? His alma mater? His love of Seinfeld? Maybe, he joked, it was a sign of "top secret Jew-havioral targeting algorithms." The mystery was solved when he heard back from the advertiser, Katan Adventures: "In order to reach Jews who haven't listed their religion on Facebook (which, by the way, is a vast majority) we run ads in metro areas with large Jewish populations and try to grab their attention with ridiculous lines such as "hey jew," but we obviously get a lot of wasted clicks with this strategty as well. And some angry emails."
Wow stalkers, and insensitive idiots.