"How do Ethiopians transfer money to the outside world online?" They don't!
The local financial network is not tied to the outside world as readily; the outbound transfer, for the obvious reasons, is very limited and controlled.
Local businesses here, as you pointed out, can transfer money to outside entities or creditors through local banks.Â
Certain businesses allow you to pay your bills (Sheraton or Hilton, for example) using major credit cards.
You can also withdraw cash using your Master cards/Visa based ATM cards from most machines.
This is my understanding.