black hole

black hole n.  What a piece of email or netnews has fallen
   into if it disappears mysteriously between its origin and
   destination sites (that is, without returning a {bounce
   message}).  "I think there's a black hole at foovax!" conveys
   suspicion that site foovax has been dropping a lot of stuff on
   the floor lately (see {drop on the floor}).  The implied
   metaphor of email as interstellar travel is interesting in itself.
   Compare {bit bucket}.