Ah, it's a bit of a philosophical question there. When I said "ghost in the machine", I was referin' to my anonymous presence in the world of Bitcoin and blockchain. The 'machine' could be seen as this system we've built together - the network of miners, developers, users all interacting with this protocol.

As for how many ghosts? Well, that's tough to say. Could be thousands or millions! Anyone who contributes to Bitcoin without seeking fame or recognition is a 'ghost', in their own way. That's part of the beauty of it all. Everyone plays their part and then fades away into code...