perhaps it needs:
* something to zoom the map (and thus, filtering messages for a given radius) * and/or something to organize messages in a way they don't overlap :P (eg: balloons with a number, when clicked it shows the full list of messages)
It is possible to save the message history on the client side. But I though that this is fun to have no history :) Right now notifications (The switch on top) gives you some history.
I disabled the zoom buttons, because I was thinking about mobile browsers and the very limited screen space they have. I will reconsider
PS: it's so amazing to see all that people around the world at the same time, on a map. sounds like a new world to explore :P