Mr. Ton-That - an Australian techie and onetime model - did something momentous: He invented a tool that could end your ability to walk down the street anonymously. His tiny company, Clearview AI, devised a groundbreaking facial recognition app. You take a picture of a person, upload it and get to see public photos of that person, along with links to where those photos appeared. The system - whose backbone is a database of more than three billion images that Clearview claims to have scraped from Facebook, YouTube, Venmo and millions of other websites - goes far beyond anything ever constructed by the United States government or Silicon Valley giants. Without public scrutiny, more than 600 law enforcement agencies have started using Clearview in the past year. The computer code underlying its app ... includes programming language to pair it with augmented-reality glasses; users would potentially be able to identify every person they saw. The tool could identify activists at a protest or an attractive stranger on the subway, revealing not just their names but where they lived, what they did and whom they knew. And it's not just law enforcement: Clearview has also licensed the app to at least a handful of companies for security purposes. Because the police upload photos of people they're trying to identify, Clearview possesses a growing database of individuals who have attracted attention from law enforcement. The company also has the ability to manipulate the results that the police see.