Bystander intervention means acknowledging inappropriate, sexist or offensive comments or acts, even though they do not directly target or affect you. These could be comments in IRC, email, or in person. It means acting against the bystander effect.
Practicing bystander intervention is part of the Allies workshop. It is a superb use of Magical Man Sparkles! Although you may be accused of White Knighting. See Good sexism comebacks for some specific things you might say.
Further reading:
- Cate Huston - It's not an asshole problem, it's a bystander problem
- Matt Zimmerman - Do not stand by (2009!)
- Bystander Intervention Can Cause More Problems Than It Solves - Storify of tweets by Lauren Chief Elk, about bystander intervention in sexual assault
- Jackson Katz - TED Talk supporting bystander intervention by men,