It's a blob. It's awesome because it reduces book keeping and doesn't waste game time on the group prepping so they aren't screwed over by some situation the GM throws at them that they forgot to prepare for. Plus, it allows them to be creative.
We play it like this:
GM: "There's a large pit in front of you, it spans about 10 feet and you can't see the bottom."
Player 1: "Ok, I'm going to throw my rope across and swing to the other side."
GM: "Cool, roll Defy Danger."
Player 1: "Ok, I'm going to take +1 for adventuring gear because of the rope *marks off 1 use*"