Hi,
  as public transport (bus, train, underground, taxi, etc) is a rather booring affair there is a great opportunity to offer informertials and advertising embedded in public service announcements. For example a customer could tune / connect to a broadcast beacon on a bus. Using messages or a simple client the beacon on the bus may broadcast the current location, the next stop and its estimated arrival time. Also it may offer some up-to-date weather forecast, traffic news likely encountered, connecting services and their estimated departure time.

  Ontop of the information a provider could offer advertising space for local businesses -- possibly tied into the location information. For example the nearest pub, the nearest fast food restaurant and any special offers available. Perhaps the location of the farmers market and when it is held next. What films are in the local cinema and the even offer pre-booking through the service.

  As the familiarity of the system grows there could be room for offering advertising space on the go. Someone offering a second hand utility nearby may be interested to sell the item in some form of small ads that can be browsed. Placing an ad could be as simple as sending a SMS message. Or anyone offering tutoring for schooling or any other activity may offer services to passengers.