User feedback
From DesignPatterns
It is important to give user's feedback while they are interacting with your system. Whether its a sign up form, a wizard, a social situation, user's need to know if they are successful or not, if they are where they thought they were going and if there is some action needed to proceed.
User feedback can be in the form of:
- Inline messages - welcoming a new user to new features
- Error messages - letting someone know (in context) that there is an error in a form or inquiry that needs to be remedied and how to go about doing that
- Success or confirmation dialogs - confirming that a transaction went through or was submitted
- Loading indicator - whether a swirly spiral or a filling horizontal bar, letting the user know that the request has been received and is being delivered. This is also important to give a sense of time elapsed and time to go so the user has a sense of context about how long the wait might be.

