Icon to edit/configure a stream - Control and label to add a new stream - Number of Inbox items - Percentage of on-boarding tasks completed - Call to action to invite your colleagues
an environment, which allows an individual to perform an action. For example, a knob affords twisting, and perhaps pushing, while a cord affords pulling. http://en.wikipedia.org/wiki/Affordance
thought process about how something works in the real world... Mental models can help shape behavior and set an approach to solving problems (akin to a personal algorithm) and doing tasks. http://en.wikipedia.org/wiki/Mental_model
is suggestive is often slightly funny is hard looks easy http://www.paulgraham.com/taste.html uses symmetry resembles nature is redesign can copy is often strange happens in chunks is often daring Principles of good design.