A quick glance on a Twitter stream, or perhaps a Facebook and you’ll probably see mentions of Foursquare with a person’s location, or perhaps a small graphic detailing, with an address, just where another person is, using Gowalla. These location based tools are frightening to some and a welcome to others, but like any emerging technology, is fun and interesting to play with. Currently the heavy hitters mentioned above will soon be joined by updates to other programs that offer similar services, Loopt and Yelp. Knowing where you are is always nice, but knowing where you are in ...