Video-game designer Zoë Quinn in the aftermath of Gamergate, an act of web harassment with world-altering implications.

A man felt wronged by his ex-girlfriend, a video game designer. So he published a 9,425-word online screed with “each component designed to be as damaging to [her] as possible.” It sparked the online fire known as “Gamergate.”

A group of journalists and researchers wade into ugly corners of the Internet to expose racists, creeps, and hypocrites. Have they gone too far?