Cody Fink for MacStories, on a little-reported tidbit about the 5S's "co-processor" (emphasis mine):
It hasn’t been said (or if it has been it’s been buried underneath a litany of other geeky details), but the M7 coprocessor in the iPhone 5s records your movement data whether you’re using apps or not. Without apps, the M7 keeps a basic log of data, determining whether your phone is in motion and how to decide if it’s an appropriate time to ping for network data.
This is very cool. I’m very excited to see what Apple has planned for the M7’s future.
I link to this M7 thing because last night I downloaded the Pedometer++ app that Fink mentions. It uses the M7 to track your steps throughout the day; as someone who walks a lot, every day, out of necessity, I’m keen to find out how many steps I’ve logged. (As of this writing, 9,955 today.)