A songwriter can write a hundred songs; then suddenly one of them really resonates with people and becomes a hit. Who knows why? It's not that it's necessarily better. But through some random circumstance or magic combination of ingredients, people love it. Once you've got a hit, suddenly all the locked doors open wide. People love the hit so much that it seems to promote itself. Instead of trying to create demand, you're managing the huge demand.
-- Derek Sivers, Anything You Want, p. 10