MailItem.Importance Property (Outlook)
Published: July 16, 2012
Returns or sets an OlImportance constant indicating the relative importance level for the Outlook item. Read/write.
This Visual Basic for Applications (VBA) example checks if the item displayed in the topmost inspector is sent by 'Dan Wilson' with 'High' importance. If it is, then it displays a message box to the user. Before running this example, replace 'Dan Wilson' with a valid name in your address book.