I used to do some work on mTurk (Amazon) many years ago. At one point I was working on the Kinect project for Microsoft. Training it to recognize heads, shoulders, elbows, hands, hips, knees and feet. I had no idea the what the work was for until after the project was released and I saw the videos of how it’s tracking worked. They paid something like .36c (usd) per frame and there were tens of thousands of images to tag. Each image would have 1-4 shadowy outlines of people in it. I made a quick macro that would click around to give me the basic shape I needed and then all I had to do was line up the all the joints for whatever poses they happened to be in. Guess I was kind of cheap human ai teaching skynet how to track our movements for the future.