Wearable activity trackers like Fitbit are one of the fastest-growing categories in personal tech. At the same time, insurance companies are looking for ways to reward good behavior. Now the trendy American health insurance start-up Oscar Health has teamed up with activity tracker Misfit Flash to offer incentives for active living. Members who sign up are given a free Misfit Flash device which is programmed to send the wearers' health data directly to the insurer. When certain goals are met the member is rewarded with Amazon credit that can be redeemed for products and services. While many people might balk at such corporate intrusiveness, if successful, the program may help make people healthier, lower insurance premiums, and spread the use of activity trackers.