I'm incredibly curious about how the HN community views devices like the Fitbit and similar products commonly associated with the so-called Quantified Self movement. Not counting the folks who simply want to track their behaviors for data geekery's sake, I assume that many people who use these devices do so for the purposes of weight loss, improved health and fitness, better body composition, etc.
Assuming that that's the case, I wonder how effective these devices really are for the average person?