Show HN: Skychalk - share thoughts on anything anywhere (like digital graffiti)

What we've created is a way to let people leave messages at any latitude/longitude point for anyone else to read (so not just venues.). There are a lot of potential uses for this: i.e. meeting your neighbors, self-guided walking tours, missed connections, local classifieds, lost dogs etc... We've made it optionally anonymous and pretty open in terms of use. We're not sure if that's a good or bad thing, but want to see how it evolves.

Right now you probably have to pan over to SF to see it in use, but it's open for use anywhere.

We'd love your thoughts.