The Washington Metropolitan Area Transit Authority (DC) is testing a feature that will enable riders to add value to their SmarTrip cards online. The pilot includes 5,000 riders, including 50 recruited via Twitter. Riders can add between $10 and $200 online but, as Greater Greater Washington notes, the system cannot instantly update the card balance. Instead, riders have to tap the card to a bus or rail target so the card can communicate with WMATA’s central servers. Link to full story in Greater Greater Washington.