Ok, little extreme but you can use Google Earth as your personal messenger. So this is the scenario, you paint on your roof “hi, how are you? The weather is great here.”, then your friend located somewhere else waits for Google to update their pictures, then when he/she spots your message, they write their greeting back and so on.
Easy as a pie, maybe not the most dynamic way in communicating but definitely fun and teaches patience. Let’s look at it this way during World War two my grand parents did all of their interaction through snail mail and it took letters up to three months to travel.
Another scenario is us getting messages out there, most of us have access to huge billboards (the roofs). For example you can now track Tour de France via Google Earth, I dare all the house owners on that way to write on their roofs “Make Peace not War!” or “Give peace a chance”.
If you find any personal messages on peoples roofs, screenshot them and let me know.
Google Earth can well be used as our personal messenger!