Tech Firms Test Online Ads to Counter Extremist Propaganda

Three experiments -- funded by Google parent Alphabet Inc., with help from Facebook Inc. and Twitter Inc. -- explore how to use the machinery of online advertising to counterbalance the growing wave of extremist propaganda on the internet, both from Islamist radicals and far-right groups. The goal: See what kinds of messages and targeting could reach potential extremists before they become radicalized -- and then quickly roll the model out to content producers across the internet.