Fix Posture has me worried. An experiment by developer Olesya Chernyavskaya, the site gets blurrier the worse your posture gets, which is something we should all pay more attention to, especially during the busy fall release season.
Fix Posture uses your webcam—the site claims it won't scrape or steal your data—to look for telltale signs of poor posture, based on the tilt of your eyes, the relationship between your eyes, shoulders, and the horizon, and the intrusion of any foreign objects like a knee or foot in the image. The site will flag those as a no-no, blurring the entire screen and only re-focusing the text if you sit up straight again. You're best off calibrating the tool with some good posture first, of course.
Now, how well it works isn't terribly clear. It certainly blurs when I slouch at all, detecting the slightest changes in how my head and shoulders overlap. I likely don't have great posture having worked at a desk for a few years now, though I do stand for half the day and my posture then is much better. I'm not convinced Fix Posture knows exactly what's best for me, but I do appreciate how it's forced me to pay active attention to desk-slouch. In tandem with some research on proper posture, it seems like a nice kick in the butt to pay more attention to my volatile body.
Unfortunately, the tool is limited to use on its homepage, though Chernyavskaya accompanies the demo with tons of notes on the design process, including both successes and shortcomings of the project. There are also links to the code base on Glitch, where you can play around with its inner workings yourself. I'd love to see it working as a browser extension, accompanied by more in-depth calibration tools and a few options for blur intensity. Someone do that. My back hurts.