Gaver presents a compact presentation of potential and possibilities of the concept of affordance in HCI/design. Gaver’s presentation is more analytic than Norman’s introduction of the concept to design world a few years earlier (Psychology of everyday things, 1998). Gaver for example categorizes four different kinds of affordances by separating the affordance and perception: falce affordance, perceptible affordance, hidden affordance, and correct rejection. In addition to this Gaver also applies the concept for complex actions and defines concepts such as sequential affordances and nested affordances to explain how affordances are part of exploration and how also non visual perceptions (haptics, sound etc.) can also result to affordances. Gaver also suggests that graphical user interface can have affordances (Norman talks about perceived affordances and separates them from affordance which is a attribute of physical objects).
From Gaver’s viewpoint the most important thing in affordances is that they link action and perception together and push us to analyze and design technologies and media in terms of actions (and especially in terms of actions the design make possible and obvious).