They provide a common vocabulary for discussing many factors in notation, UI or programming language design.
Such candidate dimensions include creative ambiguity (does the notation encourage interpreting several meanings of the same element?
), synopsis ("Gestalt view" of the whole annotated structure) or unevenness (some creation paths are easier than others, which bias the expressed ideas in a developed artifact).
The authors identify four main user activities with interactive artifacts: incrementation [creation], transcription, modification and exploratory design.
For example, a high viscosity (resistance to change) is harmful for modification and exploration activities, but less severe for the one-off tasks performed in transcription and incrementation.