The aforementioned models concentrate on the consumer market, but there's a large amount of business transacted between corporate entities via the Internet. The payment infrastructure behind I-Commerce involves activity between vendors, credit card companies, banks, Internet Service Providers (ISPs), Certification Authorities (CAs), software companies and others. ...
http://www.firstmonday.org/issues/issue3_10/bambury/
Business-to-business electronic commerce (B2B) typically takes the form of automated processes between trading partners and is performed in much higher volumes than business-to-consumer (B2C) applications.
http://en.wikipedia.org/wiki/Business_to_business