[ Robbie commented in 001030 MMDigest: ]

> [ The 9-digit extended postal code system in USA, called "ZIP+4",
> [ presumably helps automated routing within large cities, but
> [ I believe it's required only for bulk postings.

That's just about correct -- dealing with the U.S. Postal Service
a lot, I asked once.  The official answer was that "it helps track the
destination better", e.g., if the street address is hard to read or
slightly incorrect (1st Ave. instead of 1st St.) the +4 digits will
help it get to where it's going.  Many post office boxes use this as
well.  For example, my P.O. box is 49216, my zip is 80949-9216.
You'll see a lot of that, too.

If there _is_ a hang up (e.g., address mangled somehow), this will
help it get to its destination faster, but that's it.

Mike Morrey