1. A method, comprising by a computer system: establishing an online marketplace for distributing software applications, the online marketplace being accessible by devices communicating with the online marketplace over respective network connections; from the online marketplace, enabling the devices to select respective ones of the software applications and initiate testing of the selected software applications in connection with testing tools operating in respective secure testing environments that shield the devices from potential adverse effects arising from testing the selected software applications, wherein the testing tools generate testing data relating to one or more criteria for certifying the selected software applications; and for each of one or more of the selected software applications, determining whether or not to classify the software application as a certified software application based on an evaluation of the testing data generated during the testing of the software applications initiated by a plurality of the devices.