Fully functional internet (unblocked data ports for Steam as an example)
TV advert idea
email integration with all communication inside giffgaff account
Ghost gift sim
Loyalty to giffgaff rewards!
Option to disable PAC request via SMS
Letting Giffgaffers use the app and the community form if they have date or not.
Topup swipe cards.
Pay account via GIFFGAFF app