By: The Economist
A customized, constantly-updating newspaper used to be the stuff of science fiction. Now, thanks to tablet devices like the iPad, there are several. Livestand, a news app launched this week by Yahoo!, joins a field that already includes Zite, bought recently by CNN; Editions, created by AOL; and Flipboard, which Google tried to buy last year. Rebuffed, Google is expected at some point to launch its own news app, code-named Propeller.