give a location.
give a url for bob, get back the latest track point for bob.
give a starting location and a set of filters, get a list of track points back.
brampitoyo and I were outside of Jive for the pdx-refresh event. We found her bicycle. She tweeted to be in one of two places both within a block of Jive (half-and-half or ace hotel). She was at neither. She had to be close though. A continuous location app would have helped (lets assume she carries a smartphone). If GPS is accurate to at least 50 feet, it would have confirmed which side of the block to look on.
yeah. do that.