Answer:
I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?
I turn everything around, but I cannot move. When you see me, you see you! What am I?
My full powers come when my makers are dead. I await a heavy hat to put on my head. What am I?
I am a delicious way of representing data.
You hold my tail while I fish for you. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.