Though we wish we could take credit, that's Esquire's headline to an interesting think piece on the trajectory of many female pop stars: from wholesome daughters to coquettish vixens. The phenomenon's called the "Butterfly Effect" after Mariah Carey's Butterfly album, introducing the singer's bikini-clad, skin-bearing (alter?) ego. The Esquire piece's thesis: Like Nelly Furtado, Christina Aguilera, Britney Spears, and Jessica ...