Horror maestros from Stephen King to Takashi Miike have taken our ambivalent post-9/11 feelings about cell phones (they played a crucial role in nearly staving off a terrorist attack, but they were also the source of incredibly painful goodbyes) and reworked them into a vehicle for evil–ghosts, plagues, and rampaging psychos. The cell phone, in their hands, is not a tool of empowerment but another instrument of terror. Humanity’s going to hell, and you don’t dare call your mother.
The article discusses a Japanese film called One Missed Call, but I’m pretty sure cell phones are a common plot device in Japanese horror films. Mind you, I guess they’re not necessarily embued with evil in other films.