Write your message and send to any place in the world and any moment in the future.
Once your message arrives in your desired destination, anybody close enough to that place can open it.
Or use the message as Time Capsule.
Send Paper Airplanes near to the place where you are and go to collect them to win new Bottles.
You want to visit Tokyo within 10 years? Send there a bottle and, once you will visit, open it and achieve your target! Want to know somebody who lives in Venice? Send there a bottle and wait for somebody who lives there open your bottles and write back to you!
Very nice experience in Sydney? Leave a bottle there, the next person who will go there could open your bottle and see your experience.