-banking is probably the best shot. (check balance/transfer/pay/etc) -business applications (booking leave/expenses in a consulting environment where the USSD message ends up in an SAP backend.) -business applications (project management. dynamic task for the day & then quality control) -consulting (find these guys http://www.groupsystems.com/ and integrate into them so you can increase remote usage of the vote systems) -it operations (remote triggers for starting/ending jobs on servers)

when you build the app on the SIM, are you able to store more data on the SIM so that when USSD messages are sent, they are send encoded & then decrypted on the device rather then sent plain over the air? - tons of banking/payment applications here.