A system and method for determining presence information for mobile devices (104) are disclosed. Specifically, the presence information for a mobile device (104) can be determined based on whether or not the mobile device (104) is having a unique interaction with a smart tag (108). If a unique interaction is detected, then the mobile device (104) can be said to be within the presence of the smart tag (108) and the location or presence information for the mobile device (104) can be correlated to location information known for the smart tag (108).