According to Ars Technica, police have been using products like BlueJay that allow to stealthily "search all your tweets, then present results to cops."
[...] consider BlueJay, the "Law Enforcement Twitter Crime Scanner," which provides real-time, geo-fenced access to every single public tweet so that local police can keep tabs on #gunfire, #meth, and #protest (yes, those are real examples) in their communities. BlueJay is the product of BrightPlanet, whose tagline is "Deep Web Intelligence" and whose board is populated with people like Admiral John Poindexter of Total Information Awareness infamy.
BlueJay allows users to enter a set of Twitter accounts, keywords, and locations to scan for within 25-mile geofences (BlueJay users can create up to five such fences), then it returns all matching tweets in real-time. If the tweets come with GPS locations, they are plotted on a map. The product can also export databases of up to 100,000 matching tweets at a time.
|"As Facebook points out, there is no such thing as privacy on Facebook."|
|Be Seen and Unseen With Privacy Glasses|
|It's Next to Impossible to Live Offline Without Being Tracked|
|"The promiscuity with which they're revealing their customers' data creates enormous risk for their businesses."|
|"His new job tasks him with defending a different endangered species: American national security journalists."|
|Google's Self-Driving Cars Giving Rides to the Public|
|"Academics who study basic income said the pilot gives a chance to see how the idea plays in a changed economy."|
|"It’s appealing to imagine a world where artificial wombs grow babies."|
|"This created a bubble, and like housing, that bubble has now burst."|
|"You look in the mirror and see your body and your face and you think that’s you—but that’s really just the machine you’re riding in."|
|"A spacecraft may be possible that could maintain a steady acceleration into and through interstellar space without the need to carry along propellants."|
|Where AI is Currently At|
|"John Deere is the largest operator of autonomous vehicles."|
|Religious Loophole to Turn Lights On and Off During Shabbat|
|"Super-detailed scans of actual human brains that run as models on computers"|
|“Trump is what happens when you fail to understand our global problems in their interconnected, systemic context.”|