Presence Orb is a high-tech service that provides anonymized data streams that could be used in a wide variety of ways in retail and general public settings. The technology effectively 'listens' to cellphone signals and uses that information to assess where people are. This could be used for example for you to figure out how busy a store or restaurant is before you get there so you can plan accordingly.
Interestingly, Presence Orb started out as a home security system that sent alerts upon detecting unfamiliar smartphones -- but this only works if the thief has a smartphone on them. For that reason, the company began to wisely re-engineer their idea and target it towards the advertising and retail space.
To minimize privacy concerns, Presence Orb is set up to provide aggregate data on groups rather than individuals, with identification of specific smartphones only possible if the smartphone's owner gives their clear consent.