What is a Geo Drop?
The idea is that there are little USB plugs sticking out of a wall that are actually flash drives, set up in such a way that a smartphone can plug in and retrieve whatever data maybe on it.
What sort of data?
Ideally the data will be just little files, songs, pics, videos or geo coordinate data.
Isn't a flash drive and smartphones slave devices?
Indeed they are, however there may be work arounds to enable primitive hosting, maybe even simulate the uSD card that is in your phone.