Here are some of the many identities of E-Commerce:

1. B2B or Business to Business: Companies doing business with other businesses.  This will occur when a manufacture of a product sells to distributors and wholesalers who are selling to retailers. Pricing is based on the quantity that is purchased and can be negotiated.

2.  B2C or Business to Consumer: Businesses selling to the general consuming public.  This usually happens via shopping carts & online catalogues.  To receive the biggest price point on a sale, B2C is king of the identities.  B2C is also probably what you were thinking E-Commerce is when you walked through the door.

3.  C2B or Consumer to Business: A consumer submits a potential project online with a general budget that are looking for and within minutes, hours, or days the Businesses asses the project and bid on the job.

4.  C2C or Consumer to Consumer:  These are sites that offer classified ads, auctions, and forums where the consumers can sell products to other consumers. The consumers usually make and receive their purchases via online payment processing systems like ebay.

5.  D-Commerce or Digital Commerce:  Deals with the sale of electronic goods and services.  Consumers will often purchase a premium account or subscription and are billed annually for the consumption of these virtual services.

6. M-Commerce or Mobile Commerce:  Utilizing the mobile platform to purchase items with a location based model, purchase digital content, or purchase products from online vendors.