http://arstechnica.com/gadgets/news/2011/04/android-phones-keep
While Google is also using the data to improve its internal cell tower and
WiFi location database or to improve call routing like Apple, it also uses
the data to improve Google Maps and collect information about traffic
patterns. The problem with Google's data collection is that unlike Apple,
the information sent to Google contains a unique identification number that
can be tied to a particular phone. While technically anonymous, that number
could potentially be used to trace back to an individual user.
