Facebook, YouTube and Twitter have become an everyday part of life for many young people and increasingly, the way some, including rival gang members, threaten each other.
The practice is called "cyber banging," and it's often led to fights and even death.
Jaime, 17, has been in a gang for two years and is trying to leave. NPR agreed to use only his first name for his safety. Logging onto a computer at the YMCA of Metro Chicago, he clicks on a video in his Facebook feed. It shows a group of young men mugging for the camera, flashing gang signs and guns. Jaime says it's one of many so-called gang pages online.
"Social media is just endorsement, that's all," he says. "To