Microsoft takes the Tay chatbot offline after 16 hours

Microsoft launched Tay, a Twitter chatbot for 18- to 24-year-olds that learned from its conversations. Coordinated trolling pushed it into racist and inflammatory posts, and Microsoft withdrew the account within about 16 hours and 96,000 tweets.

Why it mattered An early and much-cited case of a system that learned in public being turned by users who set out to do it. Microsoft said it would fix the weakness before any relaunch.