Answer:
I will disappear every time you say my name. What am I?
If you've got me I'm everywhere. If you share me I'm nowhere. What am I?
I build up castles. I tear down mountains. I make some men blind, but I help others to see. What am I?
I am a protector of the scoreboard.
I mirror your actions.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.