Dave Rand is a researcher at Harvard University's Berkman Center for Internet and Society. He uses the system to run experiments like a classic test of altruism. He'll give the subject $1 and assign them the task of deciding how that dollar should be divided between them and an anonymous co-worker.
Dave says that the experiments he runs at Harvard are fine but since they're mostly done with Harvard undergrads as the subjects, it's not the most representative cross-section of demographics. Mechanical Turk attracts a much greater variety.
Also in this show, people watched YouTube videos 700 billion times this year. And they uploaded 13 million hours of video. That's a lot. We try to make sense of it.