We've all seen them on our Twitter streams, Youtube videos and Facebook news feeds: commenters who post hurtful and sexist opinions that degrade women. The anonymity of the internet and lack of reprimand lead some people to spread hateful opinions online, but that doesn't mean the rest of us can't show them how wrong they are. The next time you see these posts surface, don't allow yourself to be an online bystander. Commit to challenge people who make, say, or post sexist things on the Internet, especially on social media.