SpamAssassin allows the subject of an email to be rewritten if it is thought to be spam. If a user has an email client that cannot filter messages based on email headers such as
X-Spam-Status, then this feature can be used. It will assist users in separating spam from ham in their inbox.
Some email clients, such as Outlook Express, cannot filter email by using the values of particular email headers, but can use the
Subject of an email for filtering. If such an email client is used, then rewriting the subject may be the only way to automatically move spam to a folder. Email client configuration is covered in Chapter 17.
SpamAssassin applies a prefix to the subject. It is specified with the
subject_tag directive in
local.cf or ...