For more than a year, Google has been able to provide an answer to the question "Where am I?" Now it can also answer "Where are the people I care about?" On Wednesday, Google announced an upgrade to its mapping application that lets people track friends and family members in 27 countries around the globe, using a PC or a mobile phone. While some people might find this development a bit creepy or intrusive, others say such location-tracking services are surprisingly useful and fun. More than a million people have signed up for Loopt and Where.com, two of the most...