Quite a scary feature for Google mail users: according to the French JDN (web journal), Google will make available to other users the geographical localisation of users when they send e-mails with city/village, region and country.
In terms of privacy, it is obviously problematic. Other forms of communications like telephone do not give that amount of details as to the whereabouts of people. Telephone numbers for example indicate a region more often than a city. Only postal communication does give away the same amount of features. However, postal communication is not instantaneous, thus the person can have moved away by the time the other person received the message. This won't be the case by e-mail.
Nevertheless, the feature is not surprising given past relationships of Google with China and handing in dissidents.
"Google teste la géolocalisation d'e-mails avec Gmail" (JDN, 11 February 2009)