WhozThat? evolving an ecosystem for context-aware mobile social networks

One of the most compelling social questions, which until now was left unanswered by current technology, is "Who's that?" This question is usually asked about a new unfamiliar person in a social setting who piques your curiosity. This article presents WhozThat, a system that ties together online social networks with mobile smart- phones to answer this common and essential social question. WhozThat builds an infrastructure that shares social networking IDs locally, using wireless technology, while also leveraging a wireless connection to the Internet's social networks to bind identity with location. In addition, WhozThat offers an entire ecosystem on which increasingly complex context-aware applications can be built; that is, once the environment knows who one is, the environment can adapt its content based on the individual's identity or even the collective tastes of a local group. We describe a prototype of the basic WhozThat system and also describe a more advanced service we built, a context-aware music player. We also discuss security and privacy issues introduced by mobile social networks.

The Whozthat Protocol for Mobile Social Networking

The basic identity sharing protocol underlying the WhozThat system is shown in Fig. 1. Our assumption is that smartphones will soon become ubiquitous, and will possess both a local wireless capability e.g., Bluetooth or WiFi) and a wide-area wireless connection to the Internet, through either a cellular data plan such as enhanced data rates for GSM evolution (EDGE), a universal mobile telecommunications system (UMTS), evolution-data optimized/only (EV-DO), general packet radio service (GPRS), high-speed downlink packet access (HSDPA), third generation (3G), or WiFi/WiMAX. We expect this to be a reasonable assumption given current market trends and the explosive popularity of smartphones. As shown, both users' smartphones are equipped with the WhozThat identity sharing protocol, in which each mobile phone periodically advertises or broadcasts an identifier or handle such as the social networking ID of the owner of that mobile device. This handle represents a pointer to the social networking profile stored on a remote site. During the meet-and-greet phase in Fig. 1a, for example, when Anne and Dave first enter the bar, their smartphones begin wirelessly sharing their social handles with each other. Through this mechanism, each individual in a room or meeting hall learns the handles of other individuals in the same proximity.