Bob McMillan at IDG News Service runs through how it works, the current efforts, and where privacy concerns lie. In general, publicly broadcast information is hard to contain, but McMillan examines the connection between collecting millions of SSID and MAC association by location and making this available in easily retrievable form, as Google does.
Google Restarts Street View without Wi-Fi Scanningwill.i.am blew £15,000 on clothes in 30 mins