The list of most popular apps right now offers a glimpse into how people are using technology to take action.

After the killing of George Floyd by a Minneapolis police officer last week, people have flocked in record numbers to police scanner apps, where they can listen in on law enforcement’s radio communication.

People are likely using these apps in a number of ways, including but not limited to tracking or participating in protests.

Police scanners as well as Citizen offer a way for protesters to stay ahead of planned police action and to understand in real time what police are up to.

People have long used police scanner hardware to follow crime, but this new generation of apps brings that technology to more lay users.

The first iteration of the app launched in 2016 with the mission to “open up the 911 system” so that “everyone can do their part.” Many, including the New York Police Department, argued at the time that the app encouraged vigilante justice — it was literally called Vigilante — and it relaunched in 2017 as Citizen.

The vast majority of updates on Citizen come from employees who monitor various publicly available police and fire department transmissions and then post select incidents on the app and notify nearby users.

Of course, many people are likely using these apps passively to monitor what’s going on in their neighborhoods amid protests and police action.

The utility of encrypted messaging apps like Signal is more straightforward.

Protesters around the world have long used these apps to communicate with one another safely and without fear of increasingly possible police interception.

Some Hong Kong protesters even resorted to mesh messaging apps that work without an internet connection, though it doesn’t seem anxiety about police snooping has gotten that serious in the US yet.