Motivation

The problem each markup language was created to solve.

HTML

Created to let researchers share and link formatted documents over a network in a way any computer could display consistently, without needing a shared word processor or proprietary format.

XML

Created to give data interchange and document formats a strict, self-describing, vendor-neutral syntax — simpler than full SGML but stricter and more structured than the increasingly lax HTML of the 1990s.

Markdown

Created so writers could format plain text quickly using conventions already common in email and plain-text writing, then convert it to valid HTML without hand-writing tags.

AsciiDoc

Created to give technical writers a plain-text authoring format expressive enough for full books and documentation (indexes, cross-references, includes) rather than just simple formatted snippets.

reStructuredText

Created to give Python documentation an unambiguous, extensible plain-text syntax that could be parsed reliably into multiple output formats, addressing the ambiguity of earlier lightweight markup attempts.

LaTeX

Created to separate content from layout so authors could produce professionally typeset documents, especially ones with heavy mathematical notation, without manually controlling spacing and formatting.