Lars Magne Ingebrigtsen <larsi@ifi.uio.no> writes: The terms are not
   synonymous, they are orthogonal.
   
   If you tap * on an article, you have made it persistent. Nothing you
   ever do, except using the M-* command, will remove it from the cache
   where it's stored.
   
   If you mark an article with the E mark, (ie., made it expirable), it
   will be deleted by the mail backend when it reaches a certain age. The
   persistent copy of the message will not be touched.
   
   The two terms are not related.