Wi-Fi Sniffing Lets Researchers Build Graph of Offline Social Networks

angry tapir writes "The probe requests emitted by a smartphone as it seeks a Wi-Fi network to connect reveal the device's manufacturer thanks to its MAC address. This can offer some information about a crowd of people by looking at the breakdown by device brand. However, because some OSes include a preferred network list (PNL) in their probes, it may be possible to use Wi-Fi sniffing to infer even more information about a group of people by looking for common SSIDs, and potentially mapping them to known network locations (PDF). A group of Italian researchers has been looking at ways to use the information in probe requests to analyze the social connections of crowds." The idea being that if you share preferred networks (especially ones only seen infrequently) you are more likely to be socially connected.

Another example of data "leakage"

[WuphonsReach]

Eh, the better question is "why does your computer leak data other then the MAC address"? Which is exactly what the PNL (preferred network list) is doing.

Sure, it might save battery life, but information leakage like that should be off by default.