Why is there a tiny real estate sign nailed to the floor of our rented apartment?

Seattle real estate is so hot right now that I've decided I want a cut.

So I'm subletting one square foot of our living room.

What would someone do with only one square foot??

Uh, live on it I guess?

Who could----No, WHAT could live on a single foot of hardwood parquet floor?

Well... I guess it'd have to be a bunch of little things or one big thing.

And both possibilities are equally unsettling.