To the surprise of many, Google confirmed that since 2006 its Street View Cars captured WiFi network information in addition to Street View Photos. Google uses this WiFi network information to improve location-based services like search and maps. Specifically Google confessed that the WiFi information collected was:
WiFi networks broadcast information that identifies the network and how that network operates. That includes SSID data (i.e. the network name) and MAC address (a unique number given to a device like a WiFi router). Networks also send information to other computers that are using the network, called payload data, but Google does not collect or store payload data.
Not surprising that Google claims that its collection and use of the WiFi data was legal, done by other companies including Skyhook and organizations like the German Fraunhofer Institute. Around the world a number of privacy groups have been unhappy about Google Street View Photos and now new privacy concerns issues abound regarding Google's collection of WiFi network data.
Some governments have even asked Google to eliminate this data. More details in the full article on the LexisNexis Legal Technology Blog.