She made three cents for each click, or about 18 cents a minute. In 2010, her husband lost his job, and “MTurk” became a full-time gig. For two years, she worked six or seven days a week, sometimes as much as 17 hours a day. She made about $50,000 a year.

“It was enough to live on then. It wouldn’t be now,” Ms. Milland said.

The work at that time didn’t really involve A.I. For another project, she would pull information out of mortgage documents or retype names and addresses from photos of business cards, sometimes for as little as a dollar an hour.

Around 2010, she started labeling for A.I. projects. Ms. Milland tagged all sorts of data, like gory images that showed up on Twitter (which helps build A.I. that can help remove gory images from the social network) or aerial footage likely taken somewhere in the Middle East (presumably for A.I. that the military and its partners are building to identify drone targets).

Projects from American tech giants, Ms. Milland said, typically paid more than the average job — about $15 an hour. But the job didn’t come with health care or paid vacation, and the work could be mind-numbing — or downright disturbing. She called it “horrifically exploitative.” Amazon declined to comment.

Since 2012, Ms. Milland, now 40, has been part of an organization called TurkerNation, which aims to improve conditions for thousands of people who do this work. In April, after 14 years on the service, she quit.

She is in law school, and her husband makes $600 less than they pay in rent each month, which does not include utilities. So, she said, they are preparing to go into debt. But she will not go back to labeling data.

“This is a dystopian future,” she said. “And I am done.”