I second that. Pulse -- the Japanese original, not the vapid Hollywood remake -- was one of the most effectively creepy movies I've ever seen. Pulse is an amazing film, do yourself a favor and track it down. It's engaging so you need to give it your attention; it's not some movie you can put on in the background and expect to enjoy, like an action movie that doesn't require any concentration.
I saw Vanishing because I've loved every other Brad Anderson movie before this, but skip Vanishing. Not even worth renting.