What is up with UP? Released this fall, the bracelet/iPhone duo tracks our every move, telling us when it's time to wake up, when it's time to stop sitting down, what to eat, how to exercise, and who to kill. Or, at least four of those. Here's an overview, here are FAQs, and here's where to buy (it costs $99).
"Awesome? Or terrible? Or the future?" writes reader Amy D. "Or awesome? I swear I don't work for this company." But the longer we wear the bracelet, how strongly can we be sure of anything?