I talked to a lot of people about almost this exact idea in late 2011. Though I didn't build it because I got involved in something else, everyone I talked to

I talked to a lot of people about almost this exact idea in late 2011. Though I didn't build it because I got involved in something else, everyone I talked to was very enthusiastic about the idea (e.g. ready to hand over a credit card). I think you should pursue this idea further!