When I write a letter to my friend, I am sending it to her.
Now let's add a twist. I will write a letter and leave it unaddressed. The mailman I give it to doesn't mind this. In fact, unaddressed letters are his specialty. He takes my letter and roams about, destination unknown.
On his travels, a stranger sees the mailman, takes my letter from him, reads it, and starts writing a response. The letter and the response go to the mailman. He then delivers that response back to me. It turns out I can do the same with any unaddressed letter the mailman carries. So a game takes place, swapping and responding to unaddressed letters, a game that goes on indefinitely.
I think of that game as I interact on the web, a swirling collection of addressed and unaddressed letters in transit. Which unaddressed letters will I respond to? Who knows what response will turn into a series of addressed letters.