Businesses or organizations have long dealt with each other by exchanging documents. Halfat's tax receipt (355 BCE)
Document exchange is a very natural thing to do; the simplest case is "here's my catalog, do you want to buy anything" and the exchanged document being "here's my order"
In this "loosely coupled" architecture neither party to the exchange needs to know how the other produces or understands the documents, only that they can
The technology for documents has changed throughout history; we don't use pottery or papyrus or parchment any more, but the basic idea of document exchange has changed relatively little
The two-party document exchange pattern is the building block from which more complex patterns are created, such as supply chains, marketplaces, and auctions
