One of Amazon's subtler but potentially valuable promises for the Kindle Fire HD was its Kindle FreeTime mode -- a fenced-off world that would give kids a simple place to play and their parents the confidence to step away for a few precious minutes. It wasn't part of the initial launch, but a new update to the 7-inch model is rolling FreeTime into Amazon's latest tablet. The upgrade gives as much flexibility as Amazon promised, letting adults introduce filters as well as cap the time their children spend with different kinds
