If you choose to book a flight through Orbitz, Expedia, Cheaptickets (or any other third party), you will need to work with that third party to get a refund if your flight becomes available for less.  You can contact the airline directly, but chances are, they will refer you back to where you purchased the ticket.  While Yapta will track the price of flights booked through a third party, it will not alert you to a refund because obtaining one on a ticket purchased through a third-party is not assured and may prove difficult.  In this instance, Yapta will alert you only when the price drops.