Principles of UsabilityPersonal Assistant: Defending AttentionTour Guide: Manage ExpectationsUser models and program modelsExample: Windows versus Mac program modelsSet accurate expectationsMentor: Design Not Just for Usability, but LearnabilityTeach with affordancesTrainer: Provide Immediate FeedbackDirect manipulationWork with the mindUse color appropriatelyThe Context of the WebHTTPThe PageUsability on the WebKnow When to Use Ajax—and When Not ToDon’t break the back buttonDon’t use Ajax for navigationKeep Page Elements ConsistentKey CommandsIncreasing Responsiveness with Ajax (‘It’s Too Slow!’)Consequences of Increased Responsiveness (‘It’s Too Fast!’)Blank Slates, Coach Content, and Help NuggetsBlank slatesCoach contentHelp nuggetsCross-Platform DevelopmentRealities of PlatformsWhat makes a platformIt isn’t all badDealing with platform differencesThe Rails WayKnow your audienceGraceful Degradation and Progressive EnhancementSummary