The perceptual psychologist J. J. Gibson coined the term in the late 1970s to mean the relationships that an actor (person) can have with objects in the world. Then Donald Norman popularized the term in his book "The Design of Everyday Things."
You may think these affordances don't matter much. But after you have them (via using a physical task board) you will find they are sorely missing.
- Hold a task and show it to you. Now you know exactly what I'm talking about. Many virtual task board have no way of denoting a selected task.
- Pick a different task and hold it. Now I know you are talking about that one, but I'm still referring to the one I hold.
- Move a task. The motion is the affordance. Not the before and after location of a task - don't confuse position with motion.
- Pass a sticky note to you, now you have it and this denotes responsibility to perform the task perhaps. You may choose to stick it on your monitor as a reminder to perform the task later that day.
- Wad up a task and toss it on the floor. You may infer that I don't think we need this task any more.
- Retrieve a task from the floor and straighten it out and place it back on the board. Does your virtual tool have an undo feature?
- Slice the task into and hand you part of the task. Now you have a portion to own and I have a portion to own.
- Stack multiple task upon each other, this grouping may imply order or just a collection of like task.
- Annotate the task with yet another sticky note - this one could be a red sticky with an exclamation mark (meaning impeded).
- Revise the task with a simple swipe of the ink pen, to mark out a word.
- Augment the task with a new inserted word to provide more meaning with just a simple writing tool.
- Draw a diagram on the task - that's worth 1000 words!