Cidewalk is able to gain access to these apps through ad exchanges, where thousands of apps simultaneously seek to fill their ad space with the best promotions they can find. We use our proprietary technology to tell these apps to choose your promotion to fill that space. Since we strive to pair the right promotion with the right mobile user, the apps that your promotions show up on will vary depending on many factors, like the time of day, the location you choose, and the preferences of mobile users in that location.