1. A method comprising: receiving, by a device, a geocast message; determining, by the device, if memory of the device comprises a message that was sent to a region containing a geographical source of the received geocast message; when it is determined that the memory of the device does not comprise a message was sent to the geographical region containing the geographical source of the received geocast message, composing, by the device, a response message; geocasting, by the device, the composed response message; and clearing from the memory of the device, based on the received geocast message comprising a query geocast message, all messages that were created prior to a predetermined amount of time earlier than a time at which the geocast message was received.