Taken literally, this game asks you to create four one-sided narratives, letters dropped into an abandoned postbox that never receive a reply. The writers are shouting into a void, though in each case it is a very specific and personal void -- the object of unrequited love, for example.
It's a clever way to capture the very nature of a solo journaling game: after all, if you play with yourself, you can never leave the boundaries of your own imagination. You are the characters articulated by the game's rules: a writer with no audience.
But there's a way you can see this experience as distilling the antisocial side of "social" media. Every day people send million of posts, tweets, and photos into the ghostbox cloud. Even this review is going God-knows-where in the hopes that someone might read it.
Caveat: I have read but not fully played the game.