Six degrees

You may have come across the term Six Degrees most probably because of its relation to Hollywood and namely the Kevin Bacon number and the movie with the same title that featured Will Smith. The basic idea is that human beings (i.e. you and me) are connected through relationships with at most six other people. In other words pick a stranger, in average he or she will be a friend of a friend of a friend of a friend of a friend of a friend. (For those interested I strongly suggest reading Watt's Six Degrees: The new science of networks and Barabasi's Linked: How Everything Is Connected to Everything Else and What It Means for Business, Science, and Everyday Life)

At first it may seem a bit bizarre. That's probably what Stanley Milgram thought and tried his small world experiment, which was later tested using emails (e.g. look here). Participants are given an item and a recipient. If they know the recipient they can forward it directly to him or her. If not they will need to forward it to someone who they think is closer to the recipient than them. Can you guess how long (on average) the chain is?

By now your question should have been: what do all the above have to do with the message in a bottle? Well, the message could have said: "If you find this bottle please forward it to X. If you don't know him forward it to someone who you think is closer to X". If you are going to start throwing bottles in the sea, you may as well do it for the benefit of science!