Amazon Mechanic Turk is great, but not for software testing

Amazon Mechanical Turk is great for crowdsourcing jobs to workforce all over the world.  One may think it is ideal for testing software under very diverse conditions (different machines, operating systems, network environment and locations).  Unfortunately, it is prohibited to ask workers to install applications. It is reported that there are over 100,000 MTurk workers in over 100 countries.