Britain's WiFi Networks Mapped
"The information was collected by radio aerials on their Street View cars, which have now photographed almost every home in the country.
The data is then used on Google's Maps for Mobile application to locate mobile phones such as iPhones in order for users to access information relevant to the area such as restaurants, cinemas, theatres, shops and hotels."
Google defends its mapping project, which they say will help spread data about places to mobile devices. But locals are still upset that the company secretly collected the data.