Hi there, I address this on the site FAQ. I'm delivering value by making the process to post a request simple and making the results easy to get via an RSS feed. I also do this for a low margin. If someone wants to go to Amazon directly and pay workers what I pay, depending on how they value their time, they will be losing money.

Because Mechanical Turk only allows U.S. residents to set tasks (although the rest of the world can work on them). Feedback Army seems to get around that inconvenience.