Digital vigilantism is where citizens become activists and use the power of social media to share comments, demands for action, information, rallying calls etc. to counter what they see as offensive or injurious or damaging comment and behaviour.

This is not just about posting comments online but about taking actions online that have more serious consequences.

This is happening as social media has become an outlet for people angry or dissatisfied with the behaviour of other groups and institutions. This is increasingly used – sometimes for good but not always – to highlight behaviours and consequences.

An example occurred in the town of Charlottesville where a rally over plans to remove a Confederate statue were met by counter-protesters, leading Virginia’s governor to declare a state of emergency.

This led to violence that was witnessed by many local people.

Some Twitter users in the Charlottesville incident accessed private information to identify and publicly shame any and every white nationalist who took part in the rally, whether they committed a crime or not. Others, however, focused on identifying only the white nationalists seen in photos and videos committing violent acts. The digital evidence was then turned over to the Charlottesville Police Department.

In 2011 the Vancouver Stanley Cup riots broke out after the Boston Bruins ice hockey team defeated the Vancouver Canucks. Facebook vigilantes named and shamed individuals, including several young offenders, who took part in the riots. A 17-year-old, Nathan Kotylak, was named in response to an image posted online, and this led to him and his family having to flee their home.

‘Naming and shaming’, that is sharing the target’s personal details by publishing them on public sites is also known as ‘doxing’. This is quite extreme and can be very damaging for the individual concerned.

Sometimes this digital vigilantism helps the Police apprehend criminals, but it can easily backfire and damage innocent people.