Yes it does scan surrounding wifi SSID because Google Maps uses Skyhook ( http://www.skyhookwireless.com/ , belongs to Google) to geolocate users faster than just using pure GPS signal. So does Apple which also use Google Maps geolocation services on their iPhones.
My guess is that Apple is gathering all those data in order to build their own Skyhook. It makes sense, specially when you keep in mind that Apple bough the mapping company Poly9.
Besides of windows, one of the first real-world applications of this technology might be in our smartphones in order to gain in battery life.
That's what WYSIPS ( http://www.wysips.com/ ) has planned to do with their similar technology. And they seem a bit ahead.
In deed nothing new. About a year ago a man discovered that his wife's iPhone was sending about 75 Mb of data to Apple via wifi in early morning : https://discussions.apple.com/thread/2450738?threadID=245073...
It turned out it was dumps of GPS data and other stuffs.
II / C / 1 / a. :
"Second, to help Apple update and maintain its database with known location information, Apple may also collect and transmit Cell Tower and Wi-Fi Access Point Information automatically. With one exception, Apple automatically collects this information only if the device’s location-based service capabilities are toggled to “On” and the customer uses an application requiring location-based infomiation. If both conditions are met, the device intermittently and anonymously collects Cell Tower and Wi-Fi Access Point Information from the cell towers and Wi-Fi access points that it can “see”, along with the device’s GPS coordinates, if available. This information is batched and then encrypted and transmitted to Apple over a Wi-Fi Internet connection every twelve hours (or later if the device does not have Wi-Fi Intemet access at that time)."
My guess is that Apple is gathering all those data in order to build their own Skyhook. It makes sense, specially when you keep in mind that Apple bough the mapping company Poly9.