This asirra thingie is for determining if a user is human. It involves cute doggies and kitties, and you can even find out how to adopt them while you are at it!
Did I mention CUTE DOGGIES AND KITTIES?!?!
I often fail at those "are you human" tests myself, where they ask you to type in the letters and numbers you see, but they are skewed, and I screw it up like 25% of the time.