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Versions: 00                                                            
Integralis Ltd                                            Graham Klyne
Internet draft                                              Integralis
<draft-klyne-addressing-00.txt>                          February 1997
                                                  Expires: August 1997

             E-mail addressing: the worst of all worlds?

Status of this memo

  This document is an Internet-Draft.  Internet-Drafts are working
  documents of the Internet Engineering Task Force (IETF), its areas,
  and its working groups.  Note that other groups may also distribute
  working documents as Internet-Drafts.

  Internet-Drafts are draft documents valid for a maximum of six
  months and may be updated, replaced, or obsoleted by other
  documents at any time.  It is inappropriate to use Internet-Drafts
  as reference material or to cite them other than as ``work in

  To learn the current status of any Internet-Draft, please check the
  1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow
  Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
  munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
  ftp.isi.edu (US West Coast).

  Distribution of this document is unlimited.


  This memo is a critique of Internet e-mail addressing, with
  particular reference to its suitability for use in a general
  purpose interpersonal communication medium as opposed to its
  present use largely within a restricted community.

  The critique focusses on the differences between e-mail addresses
  and other forms of addressing with which very many lay people are
  intimately familiar.

  This memo does not offer any solutions to the issues raised;
  rather it is hoped to provoke some debate on the matter.  The
  author would be particularly interested in views from those whose
  natural language does not use the Roman (western) alphabet.

Klyne                                                         [Page 1]

Internet draft            E-mail addressing              February 1997
draft-klyne-addressing-00.txt                     Expires: August 1997

Table of contents

1. Introduction...............................................2
2. Human addressing techniques................................2
3. E-mail addressing issues...................................3
4. Conclusions................................................4
5. Security considerations....................................4
6. References.................................................4
7. Authors' address...........................................5

1. Introduction

  E-mail is a communication technology which has grown out of a
  scientific and technical community of computer users, many coming
  from an American or Western European cultural background.  It is
  relatively recently that the use of communication using electronic
  computers has been extended to a population who are not computer
  technicians.  Even today, e-mail is used mainly by corporate
  information workers and computer users.

  Many of us who can and do use e-mail on a regular basis see it as a
  relatively cheap, efficient and powerful tool for communicating
  with other people around the world.  Quite naturally, we would like
  to see many more people avail themselves of the considerable
  advantages of this type of technology.

  Many members of the general population are excluded from making
  effective use of e-mail as a means of communication.  Identifiable
  reasons for this are:

  o  The cost of equipment and facilities required.

  o  The level of apparently spurious technical knowledge needed to
     operate the system.

  Ongoing developments seem to be very effectively driving down the
  costs, and efforts on many fronts seem to be reducing the
  requirement for technical knowledge (user interface developments,
  system auto-configuration, network appliances, special-purpose
  systems, etc.)

  But the area of addressing presents a continuing conceptual barrier
  to e-mail use for non-technical users.  This thesis is explored in
  the remainder of this memo.

Klyne                                                         [Page 2]

Internet draft            E-mail addressing              February 1997
draft-klyne-addressing-00.txt                     Expires: August 1997

2. Human addressing techniques

  There are (at least) two techniques for adressing which are widely
  used and understood by the non-technical population:

  o  Postal addresses

  o  Telephone numbers (including fax numbers)

  Postal addresses are often applied by hand (and are always capable
  of being applied by hand), and may employ an arbitrary range of

  Telephone numbers are generally applied by direct entry on a
  telephone device, as a sequence of numbers and, possibly, star
  ("*") and hash ("#") characters.

  (By "applied", it is meant here that this is how the addressing
  information is specified to the communication system uses the
  address to locate the addressee.)

  In either case, the equipment needed to apply the address is very
  compact and simple to operate (a pen, or a numeric keypad).

  In each case, the system of addressing works well and with
  international scope.  In the case of hand-written postal addresses,
  the full range of local symbols (e.g. accented letters, non-Roman
  alphabets, ideograms) may be used so the address can be expressed
  in a form which is familiar to the user.  In the case of telephone
  numbers the address is reduced to a very small set of symbols so
  that (at worst) there are only 12 new symbols that the user must
  learn in order to use and apply the address.

3. E-mail addressing issues

  What are the requirements for an e-mail address?

  o  It has to be applied by the sender of a message.

  o  It also has to unambiguously specify the e-mail destination to a
     purely mechanical communication system.

  The first requirement suggests that the mechanism for applying an
  address should be very simple for a human user.  The second
  suggests that address entry must in some way interface directly to
  the communication system.

  So where does Internet e-mail addressing fall short?  It is the
  author's contention that it is in the compromise between an address
  which is meaningful to a human user, and the requirement for
  machine-usability.  SMTP e-mail addresses are defined in RFC 821

Klyne                                                         [Page 3]

Internet draft            E-mail addressing              February 1997
draft-klyne-addressing-00.txt                     Expires: August 1997

  and RFC 822 [1,2] as consisting of a sequence which may contain any
  of the 128 US-ASCII characters 0-127.  The result is an address
  which is often quite long, only partially meaningful to human
  users, yet generally requires a relatively bulky and complex item
  of equipment (an alphanumeric keyboard, typically with more than 80
  keys) to apply the address.

  While e-mails are mostly text messages generated on computers by
  correspondents used to working with the Roman alphabet, the
  requirement for a alphanumeric keyboard to enter the address is not
  an issue, as it is also needed to prepare the message.  But as one
  looks to multimedia messaging in which typed text may not play a
  part (e.g. fax images, photographs, voice, video, etc.) it is not
  difficult to imagine a variety of messaging terminals for which an
  alphanumeric keyboard would have no part to play in preparing a

  If the alphanumeric keyboard were a truly user-friendly device, its
  complexities might be forgiven.  But for a large majority of the
  world's population it would be as alien as hand-written Chinese
  characters to a typical American or European.

  The essence of the problem, then, is that the character set used
  for Internet e-mail addressing, while it may have suited the
  community for whom e-mail was originally developed, is both too
  large and too limited.

4. Conclusions

  The Internet e-mail adressing scheme has been presented
  provocatively as "the worst of all worlds" by virtue of the fact
  that it has neither of the virtues of two current widely-used
  addressing schemes: postal addresses (easy for users to understand)
  or telephone numbers (easy for users to enter mechanically).

  This is not intended to belittle the inspired seminal work of the
  Internet e-mail system designers.  Internet e-mail has provided
  sterling service to the community for which it was designed, and
  many more besides.  In those days, nobody really considered that
  the Internet would grow to become a truly global communication
  system accessible to all.  Just as the Internet community have had
  to review the fundamental IP addressing system to deal with
  unexpected levels of adoption, maybe it is also necessary to review
  e-mail addressing mechanisms to achieve a scope of deployment not
  anticipated by the original design.

  The most obvious example of a widely adopted addressing scheme
  which is accepted by an automated communication network is
  telephone numbers.  They are easy to enter, reasonably compact and
  provide unambiguous call routing.

Klyne                                                         [Page 4]

Internet draft            E-mail addressing              February 1997
draft-klyne-addressing-00.txt                     Expires: August 1997

  It seems that there are two approaches which might be adopted: to
  move toward a minimal addressing scheme similar in style to the
  telephone number plan, or to move toward a truly user-friendly
  addressing scheme which can express the full variety of addressing
  that users are used to dealing with, and develop technologies (e.g.
  OCR, voice recognition) to apply such addresses using simple,
  compact terminal equipment.

  This memo has concentrated on SMTP e-mail addresses, but similar
  arguments might also be applied to the system of Universal Resource
  Identifiers (URIs) employed by the World Wide Web.  URIs are
  defined in RFC 1630 [3] to contain a substantial subset of US-ASCII
  characters.  Even allowing for hexadecimal coding, characters are
  limited to an 8-bit character set (2 hex digits).  Other electronic
  messaging systems may also be seen to suffer from similar

5. Security considerations

  Security considerations are not discussed in this memo.

6. References

[1]  "Simple Mail Transfer Protocol",
     J. Postel,
     STD 10, RFC 821, August 1982.

[2]  "Standard for the format of ARPA Internet text messages",
     D. Crocker,
     STD 11, RFC 822, August 1982.

[3]  "Universal Resource Identifiers in WWW",
     T. Berners-Lee,
     RFC 1630, June 1994.

7. Authors' address

  Graham Klyne
  Integralis Ltd
  Brewery Court
  43-45 High Street
  Reading, RG7 5AH
  United Kingdom

  Telephone: +44 1734 306060

  E-mail: GK@ACM.ORG

Klyne                                                         [Page 5]