“Sometimes it makes me feel paranoid, and afraid knowing that there is a lot that goes on,” she said. “It does give me some comfort knowing my surroundings, but I’m always torn between wanting to know and see everything, or to have that blind eye toward everything.”

Conflicted enthusiasm is a common sentiment among Citizen users: I don’t know if I want to know, but I can’t not know. In any case, it’s free, it’s right there, and it’s always refreshed. It’s a new feed. And as with our other feeds, it can be hard to look away.

Other feeds are full of friends and photos, made for you to see. This one is full of information that feels faintly illicit. To new users, the app itself can feel like a bit of a mystery, too. Where does it come from? How does it work? What … does it want? Here’s what we know.

Who?

Before there was Citizen, there was Vigilante, founded by Andrew Frame, formerly of the internet-based phone company Ooma. “Vigilante is a new technology that opens up the 911 system,” said a launch announcement for the app in 2016. “With Vigilante,” it continued, “vital information is unlocked and everyone can do their part.” This sounded an awful lot like, well, a prompt for vigilantism. At the time, the New York Police Department issued a critical statement: “Crimes in progress should be handled by the NYPD and not a vigilante with a cellphone.” Soon thereafter the app was removed from Apple’s App Store for violating the company’s policies.

But Citizen is Vigilante, redesigned and relaunched, with a less of an emphasis on what it might get you into, and a bit more on what it might let you avoid. The NYPD spokesman at the time the department was disavowing Vigilante, Peter Donald, now works for the company, and was the employee who responded to questions about the app.