Sound Capsule

I've been having a lot of fun with the ESP8266 lately and exploring the various consequences of being able to wire up arbitrary things with Wifi for very little money. One wild idea that popped into my head is somewhere between Geocaching and a public art project, which I call a Sound Capsule.

A Sound Capsule is a public Wifi network, but when you connect to it there's only one webpage you can reach (like those awful airport wifi networks). The page has a little audio player on it that plays some sound, and a button that lets you record your own audio for the next person to listen to. However, you can only record one thing at a time; the previous one gets deleted. The device itself would be a self-contained solar/battery type rig so you could hide the physical components away somewhere safe; you only want people to interact with it as a mysterious Wifi network.

I think it could be pretty interesting seeing what people do with it. Would it just be all random trolling or would people actually leave interesting messages? Maybe you could have a whole conversation with a stranger. Or maybe people would just make silly noises. It really feels like it could go either way.