exploiting dan bricklin's essays:

'Word processors are designed for writing for paper ... They evolved for the purpose of producing paper output. (in good documents)

'General purpose personal computers were still in the future, and each computer was built specially to do word processing. With the advent of inexpensive video computer screens, the connection to the typewriter as input device was broken. Some early devices tried to avoid this break, and simulated the look and feel of a typewriter by making the screen act as much like a piece of paper as possible, even going as far as having margin setting levers that were under the screen just like those under paper on a typewriter. These devices kept the page orientation.' (history of word processing')