Quantified Self is a collaboration of users and tool makers who share an interest in self knowledge through self-tracking.  You can learn more about this fast-growing, worldwide movement at http://quantifiedself.com . Self-tracking covers a wide spectrum.  Some are working to improve their health and fitness by tracking weight, exercise, sleep, or nutrition.  Others want to gain insight into their emotions.  Still others aim to improve their productivity and effectiveness by measuring how they s …