This appendix contrasts two points of view:
XML is a very flexible technology. You can use it effectively for purposes that fit either of these points of view, even though its origin was in the paper (i.e., document) world. However, people accustomed to taking one point of view sometimes experience great difficulty in grasping the other. Even after they understand the other viewpoint, they tend to initially consider things from their accustomed point of view and assume that most of the universe of interest is best viewed from that perspective.
Much of the IETF's traditional work has concerned low-level binary protocol constructs. These constructs are almost always viewed from the protocol point of view. The W3C, in contrast, has concentrated on human presentation syntaxes and higher-level application constructs that tend more toward the paper point of view. Protocol design by those who take the paper point of view can be problematical.
This appendix defines and contrasts these two points of view. Each viewpoint is exaggerated for effect. The exaggerated paper point of view is given in paragraphs headed PAPER. The exaggerated protocol point of view is given in paragraphs headed PROTOCOL.