UI density refers to the amount of information and value a user interface provides within a given amount of space and time. Matthew Ström highlights how high UI density allows users to accomplish more in less time and space. Optimizing for UI density is about striking the right balance between visual, temporal, and value density elements.

Key Points:

• Visual density alone is an unreliable measure of a UI's effectiveness. Our perceptions can be biased.

• Information density focuses on maximizing useful data/information while minimizing non-data elements.

• Design density considers the intentional use of gestalt principles to communicate meaning efficiently.

• Temporal density is about reducing wait times and optimizing the perception of time between user actions.

• Value density is the ultimate goal - providing maximum value to the user with minimum time/space requirements.

• Counterintuitively, higher visual density isn't always better. The focus should be on increasing overall value density.