Add "what you need to know for Pokemon GO clients"

README.md

@@ -8,3 +8,12 @@ Currently contains basic support for S2Cell
 
 More details and examples to come later.
 
+What you need to know for Pokemon GO clients:
+
+```javascript
+var cell = S2.S2Cell.FromLatLng({ lat: 40.2574448, lng: -111.7089464 }, 15);
+
+cell.getNeighbors(); // [ cellLeft, cellDown, cellRight, cellUp ]
+
+cell..getLatLng(); // { lat: 40.2574448, lng: -111.7089464 }
+```