Let's divide content into two broad groups: Content without well-defined form (Formless Content), and Content with well-defined form (Definite Content). Formless Content can be reflowed into different formats and not lose any intrinsic meaning. It's content divorced from layout. Most novels and works of non-fiction are Formless. Content with form — Definite Content — is almost totally the opposite of Formless Content. Most texts composed with images, charts, graphs or poetry fall under this umbrella. It may be reflowable, but depending on how it’s reflowed, inherent meaning and quality of the text may shift.