How users react to delays in a user interface, whether website or application. The 3 main response time limits are determined by human perceptual abilities.| Nielsen Norman Group
Testing how well people understand a link's first 11 characters shows whether sites write for users, who typically scan rather than read lists of items.| Nielsen Norman Group
Across many tasks, learning curves show an initial learning period, followed by a plateau of optimal efficiency.| Nielsen Norman Group
On the average Web page, users have time to read at most 28% of the words during an average visit; 20% is more likely.| Nielsen Norman Group
Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.| Nielsen Norman Group