It is a good idea for a service, if possible please consider something like https://www.mobileworks.com/ as vincvinc mentioned below that tries to be socially responsible for crowd sourcing instead of mturk.
At the kind of scale I would use it at I would just hire personal assistants.
That said, I've actually used mechanical turk to earn money in some of my low points (was living in my car working on a startup, out of cash, crazy/long story). I didn't make US minimum wage, but if I were living in Bangladesh, for example, it would have been OK money.
