The New York Times' Bits blog has this to say about a loop-hole when you use Google Maps mobile which has the My Location feature to do a search for say a close-by business:
The payoff for Google from building out its mapping service is to get people to conduct searches from their cellphones. This is a nice feature. Push a button on the map software, type “Starbucks” and it will display a map of the closest source of a latte fix, based on the cell tower or GPS data. The catch, is that this query, with your location, is entered in Google’s log files along with your phone’s unique ID.
So, the "My Location" feature itself will not uniquely identify you. But doing a search will uniquely identify your phone, and tie it to a location. That is a damned good catch by the Bits blog, I say!
Needless to say, if Google wants, it can tie your uniquely identifiable phone to the uniquely identifiable Google login ID you might use on the phone. I am not saying that Google does that. I am saying that Google can do that. Perhaps, under pressure from a subpoena or the Chinese government?
[via the The New York Times' Bits blog]