Many people read the blog from outside the United States. All these readers learn about Mechanical Turk and are excited about the concept, so they want to try it out. Unfortunately, no such luck! You need a US credit card to be able to fund the account (or you need to work as a Turker to accumulate the amount necessary to fund your own tasks.)
So, many people are asking: Why Amazon does not open the service internationally? Why restrict Mechanical Turk only to people that have US credit cards?
This was kind of puzzling to me as well, given that other Amazon Web Services (e.g., EC2, S3, etc) are open to international customers. Why other web services are open but MTurk is not?
Today I met with John Hoskins, Senior Manager of Business Development of Mechanical Turk, and asked the very same question. The answer was clarifying: For all other web services, the customer is consuming Amazon services and pays Amazon. For Mechanical Turk, Amazon receives funds from requesters and then distributes them to workers.
This flow of payments forces Amazon to comply with the US Patriot Act, especially the provisions about money laundering and financing of terrorist activities. The basic idea, known as the "Know Your Customer (KYC)" doctrine, is that Amazon should know from whom they get money and to whom they send the money. This is possible for US credit cards and for US bank accounts, due to the regulations of the US banking system. (I also guess that this is also possible for India, given that Amazon now pays workers in India using rupees.)
I find it kind of fascinating that Mechanical Turk could be used as a venue for money laundering but, in retrospect, not unlikely. In fact, given the relatively low fees that Amazon charges for funds to change hands, it is almost appealing. I can easily see a person posting one million $10 do-nothing HITs, available only to a single qualified worker, who can then consume them and get paid "clean" money.
I guess the news is a disappointment for many aspiring international requesters, but there is some hope: If you can open a US-based credit card (e.g., have a pre-paid credit card or a gift credit card), then it should be possible to open a Mechanical Turk requester account. Or, simply go and use CrowdFlower that will serve as an intermediary and submit your tasks to Mechanical Turk, providing many other value-added services along the way (thanks to Sérgio Nunes for reminding me about that!).