Postmasters in Sweden and Denmark are looking into a clever system of vending postage that a cash-strapped U.S. Postal Service might do well to consider: selling stamps via text message. The system is supposed to roll out in Denmark in April, The Local reports, and Sweden may deploy a similar system later this year.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.