Can someone please tell me what ZFS is?

And why I should care about it? I’m getting bombarded with email about some announcement that My Little Pony made where he claimed that Apple will be using something called ZFS in Leopard. I’ve called my techies down in the software bunker and asked them to look into it. As soon as I figure out what this thing is, I’ll let you know. I tried to figure it out by reading the Wikipedia entry but Jesus H. Christ it’s nothing but gorp.