The definition of storm (such as in Grapeshot) is:
Storm (When you play this spell, put a copy of it onto the stack for each other spell that was played before it this turn. If the spell has any targets, you may choose new targets for any number of the copies.)
Does Storm count the spells played by the opponent?
This definition does not specify if the spell are played by the controller of the "Storm-card" or by the opponent. I read this article and it does not clarify my doubt.
I ask this because the owner of my local shop told me that Storm does not count enemy spells and he is a kind of judge.