On any given day, I walk about 14,000 steps, or 7 miles, and burn 2,650 calories. I walk less when I work from home, by a factor of about 2x. I sleep 7 hours per night, take 14 minutes to fall asleep, and wake up an average of two times per night. I run more than my wife, but less than (many of) my friends.

All of this data comes from an experiment, running about three months now, with carrying a personal fitness tracker by Fitbit. The little device sits in my pocket and records how active I am throughout the day. With it, I know my general level of activity as well as the intensity of specific workouts, and all of this data uploads to an online profile to be shared with a circle of friends. And while the little gadget certainly hasn't revolutionized my life, the ability to be aware of and engaged with my own fitness is pretty appealing.

As it turns out, a lot of people are banking on exactly that idea.