Electronic funds transfer (EFT) : the oldest large-scale e-commerce root. Banks have been exchanging financial transactions through Automated Clearing Houses for decades.
Transaction automation (TA): consumers and businesses have been using TA in a variety of Point of Sales (POS) applications, like credit-cards, purchase scanning, etc. Verifone was the pioneer.
Inter Organizational Systems (IOS): business to business commerce over proprietary networks particularly for order entry and purchasing, using Electronic Data Interchange (EDI) technology and standards.
Electronic Commerce today: business to business (B2B), business to consumers (B2C), consumers to consumers (C2C).