- Interaction - refers to the interaction of the learner with the learning materials, and not so much with other learners.
- Usability - Downes focuses on (only) two aspects of usability: consistency and simplicity.
The simplicity principle seems rather straightforward, and Downes refers to examples such as Yahoo! or Google, which offer very simple interaction, avoiding pull-down menu's or other fancy designs.
The consistency principle is not an easy one: do you want your materials to be (only) internally consistent or also externally consistent. Internal consistency refers to having the same 'look and feel' throughout your learning materials, in order to make interaction with the materials more predictable. External consistency would then refer to an adherence to well-established standard 'look-and-feel's from web-based or other applications: e.g. do you want your materials to have a 'Microsoft Office'-type interaction, so that interaction with the material becomes even more predictable?
- As Wilfried Rubens - a Dutch edublogger - remarks, the priciple of relevance is the hardest nut to crack. Relevance is 'in the eye of the beholder', and is contingent upon the 'learning' situation, the particular need, and even the humour of the learner. Therefore the principle of relevance is very hard to operationalise and use in evaluating the effectiveness of e-learning.
For a Dutch-language discussion of this article, I refer to edublogs.be