tudborg covered a lot of good points. Another alternative to a geohash would be to use a GeoJSON[1] object to define location. It's a fairly widely adopted geog

tudborg covered a lot of good points. Another alternative to a geohash would be to use a GeoJSON[1] object to define location. It's a fairly widely adopted geographical standard and means you could throw the data from the API straight into a map (leaflet) or a database (mongoDB has native geoJSON support). [1]: http://geojson.org/ http://geojson.org/ Be careful with broadcasting your date of birth widely. It's surprising how little information is needed to open a store credit card.