@KaseiJin,
Is God dead? Nietzsche's Zarathustra thought so.
St. Anselm's famous ontological argument says, essentially, that God must exist because God's existence is not dependent on anything; it is greater to exist independently of anything than to depend on something else for existence. But Nietzsche notices that God's existence depends upon humans who believe in His existence. If humans can decide not to believe in God, God in the classical sense must be dead.
But we should ask: if no one believes in gravity, does gravity cease to exist? The answer seems to be that gravity continues to exist independent of man's belief.
I think Nietzsche forces us to reconsider the way we think about God. If God is believed by an individual, God becomes integral to the individual's perspective of the world. If an individual does not believe in God, God is a distant concept with little influence over a person's perspective.
Hunter Thompson's character Raoul Duke remarks "Lord, you better take care of me otherwise you'll have me on your hands." If Duke does not find evidence of God's mercy as he flees Las Vegas in terror, Duke will be forced to reconsider his belief in God - and the reconsideration could possibly lead to God's death, something God would, presumably, not want.
If we step back and try to imagine what Nietzsche's declaration means socially, we can say this: God has lost His universal applicability. It is up to the individual to decide whether or not God exists. When a person believes in God, this belief has an influence on the person, and therefore, an influence on anything the person influences. In this way, God exists, through His influence upon individuals and their influence upon the larger world.
Of course, the clever theist will turn this back toward Anselm's argument for aseity: God necessarily exists, but His influence is determined by the belief in Him.