I am completely ignorant about the legal hoops involved w/food prep/selling, though I feel it's implicit in the open-ness and formality of sites like Housefed/Munchery/Mealtik that they consider themselves legal, at least by some interpretation (like room & board? like school bake sales? Like farmer's markets with prepared food? I am legally clueless... yet can think of many places in life where I'm paying for food in non-traditional environments.)
Just as AirBnB has come under fire from "real" hotels in NYC, I'm sure this will food-at-home will come under bureacratic heat... if it gets traction.
(Even in Portland, which I think just passed 600(!!) food carts in 2011, "real" restaurants decided (years too late) to start complaining that food carts weren't legit (though they do have health inspections, business licenses. http://www.portlandfoodanddrink.com/2010/09/are-food-carts-g... ))
If it's not too troublesome, can you go into where you think the hard line is for in-home food selling?