What are the E-Commerce Models?

There are Lots no of Models are there for E-Commerce,but basically only 5 Models are very Populars.

(1) B2B (Business to Business)
(2) B2C (Business to Customers)
(3) C2C (Customers to Customers)
(4) G2B (Government to Business)
(5) G2C (Government to Citizens)