what does it mean when a skateboard deck has ''pop''?

Answer 1

On a new board the tail and nose of the board (along the bottom edge) are very round and that gives you the "pop" As you skate more it gets worn down and flattened, making it more difficult to ollie or do other tricks well because it doesn't hit the ground the same way.

Answer 2

I'm pretty sure that means that it ollies well.