From SGML to SML

SGML (Standard Generalized Markup Language)

ISO standard, 1985.
Huge amount of "document archive" applications in government, military, industry, academia, ...
A successfull well-known application: HTML is designed as a simple application of SGML.

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XML

W3C Recommendation 1998.
A simple subset of SGML. Targeted for Web applications. Now de facto standard.

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Canonical XML (www.w3.org/TR/xml-c14n)

W3C Working Draft, June 2000.
No DTD or general entity references, "canonical" representation.

SML (Simple Markup Language) (www.xml.com/pub/1999/11/sml >and www.xmlhack.com/read.php?item=205)

Web community discussions, 1999
Even simpler: no processing instructions or comments, UTF-8 and UTF-16 only, considerations on element attributes, white-space,...

Occam's razor: "one should not increase, beyond what is necessary, the number of entities required to explain anything"