A wireless networked device incorporating a display, a video camera and a geo-location system receives geo-located data messages from a server system. Messages can be viewed by panning the device, revealing the message's real world location as icons and text overlaid on top of the camera input on the display. The user can reply to the message from her location, add data to an existing message at its original location, send new messages to other users of the system or place a message at a location for other users. World Wide Web geo-located data can be explored using the system's user interface as a browser. The server system uses the physical location of the receiving device to limit messages and data sent to each device according to range and filtering criteria, and can determine line of sight between the device and each actual message to simulate occlusion effects.