Imagine a map on which many people collaborate at the same time. Imagine you see the edits happening in real time and you can also see the position of your collaborators and their current view on the map. A Google Docs for maps so you will. Imagine this map in a web-browser that runs on a mobile phone. Imagine not a single bit of data has to be stored on a central server but people are all acting as nodes storing the data in their browser.... and it still works offline..... With the rise of HTML5, including websockets and indexeddb, this is now possible. We created a concurrent online webgis where an unlimited amount of people can do collaborative work on a map in real time. A combination of Openlayers, Websocket and Indexeddb makes it possible to see and update each others edits and location. When people go offline their edits are stored for later synchronisation with their peers. This makes it very useful in unreliable network conditions. The tool has already been deployed in a few test cases. In low level educational projects where students share data with their smart-phone and create a common map. Also during wildfires where officers in the field regularly update the situation for the commanders in the control room. This is just the beginning, new HTML5 capabilities like WebRTC will open up new roads in map-making. Maps will become more dynamic and social, where (map)data will be directly shared between peers. Also if you get bored you get to make a map together with everybody else in the room.