Jonas Löwgren also writes about Interaction design and digital materials.

“The recommended use of the term interaction design is limited to products and services, which more or less rely on digital materials for their realization. This is due to the significance for a design discipline of knowing its respective design materials. It is impossible to design interaction per se, even though the term unfortunately implies otherwise, but what interaction designers do is to create conditions for interaction. It is possible to make some things more likely to happen, others less likely, and the way in which this is accomplished is by shaping the digital materials into tools, props and media for others to appropriate and use.” Jonas Löwgren

http://www.interaction-design.org/encyclopedia/interaction_design.html

I firmly believe this is the direction to take for future interaction design projects. The design of a product, digital or even non-digital, to imply, direct and even dictate a users actions to have a beneficial outcome even though the answer or result may not be fully evident whilst the user is “interacting” appears intriguing, interesting and ill-defined/ open to exploration.