Activists in Brazil are finding people who send abuse online and posting their messages on giant billboards near their homes.
The "Racismo Virtual, Consequencias Reais" ("Virtual Racism, Real Consequences") campaign is led by a civil rights group called Criola.
According to the BBC, Criola uses geolocation tracking on Facebook and Twitter to find out where people have sent the abuse from and then buys up local advertising space to re-publish the messages - albeit with the perpetrators' faces blurred.
Criola's founder Jurema Werneck explained to the BBC that the campaign started after weather presenter Maria Julia Coutinho was abused on Facebook.
Those people think they can sit in the comfort of their homes and do whatever they want on the internet. We don't let that happen. They can't hide from us, we will find them.
- Jurema Werneck