messagebox - Should flash messages fade out or contain a close button or stay forever?

Note: By flash message, I do not mean Adobe Flash, but messages that should be displayed on completion of an action.

I am designing a web application and messages will be displayed after a certain action.

There are 2 scenarios where this will happen:

• 
  

  User performs an action such as delete or create new user. After the action is performed, they get redirected to the main view (which in this case would be a list of all users) and a flash message is shown.

  
  


• 
  
  

  User performs an action such as saving a blog post. After the action is performed, no redirection happens. The user remains on the same page, but a flash message is displayed.

  
  

The flash message is just a simple stylized div:

^{download bmml source – Wireframes created with Balsamiq Mockups}

Problem: What should with the flash message?

• Should the message have a close button to be closed by the user manually?


• Should the message fade out automatically?



• Should the message just remain there permanently and be uncloseable?

Answer

Anything the user will take for granted should fade away.

For example:

• Message has been sent after clicking "send"


• Item has been deleted after clicking "delete"


• Contact has been added after clicking "add"

Items that should remain visible are mission only critical things like:

• Incoming call (someone is waiting for you on the other end and needs your response!)


• Message failed to send after clicking "send"


• Your entire hard drive is being erased in t-60 seconds, 59, 58, 57...

If the user assumes the task has been completed, fade it out. Only show it briefly to reassure them.