[EC1]

Wonderful. I'm founder @ parcel.io and we're doing just this. For regular people to just discover data. We have a few built in layers, one for history, politics, etc. When you enable them, you can view a layer of locations in that categories specific color. Lets say I walk beside a certain monument, I can grab data of it (pictures/videos/text) and learn more about it by being in proximity.

[sharemywin]

is it similar to foursquare?

[EC1]

Nope. You don't check in everywhere. It's literally like picking up/dropping off/tracking packages, just it's virtual data instead of a physical package.