Feedback is receiving information about the action that has taken place. A lack of response indicates shaky/poor feedback. The examples we have chosen include the recent Apple maps design, the pinwheel that appears when a Mac is not responding, and the ability of Facebook to send notifications to your account.
Shaky Design Example: Apple Maps
Another Shaky Example: Apple Computer Not Responding
Good Design Example: Survey Monkey
http://www.surveymonkey.com/ (after you submit a response to a survey, you are notified)