This game is a participatory game, an MMO masquerading as an MMO.
The conceit is that you are playing an old, defunct MMO which you discover is (Spoiler - click to show)connected to multiple universes. As you play, you find messages left by others. You have the option to leave a message, and doing so lets other people really see it.
I saw messages from real people I know, but they all soon disappeared. I wandered through an empty maze, seeing messages by people that could be real or fake. I left a message everywhere I went. Overkill, maybe? Shouting into the void? It's hard to know.
Very fun concept. Large game.