The present invention discloses an email application that includes a subject evaluation engine, which is able to automatically generate a subject heading suggestion for an email message based upon content contained in the email message. The subject evaluation engine can also compare a pre-existing subject heading of the email message against content contained in the email message. User selectable interface elements can be included in the email application for invoking the suggestion and comparison functions of the subject evaluation engine. Further, the subject evaluation can automatically be initiated before an email message is sent, can be used to notify a user when the message's subject is inconsistent with the message's content, and can suggest one or more replacement subject headings for the current heading.