Overview
ReStructuredText (aka ReST, reST, or RST) is an easy-to-read, what-you-see-is-what-you-get plaintext markup syntax and parser system. It is useful for in-line program documentation (such as Python docstrings), for quickly creating simple web pages, and for stand-alone documents. ReStructuredText is designed for extensibility for specific application domains. It is a candidate markup syntax for the Python Docstring Processing System. ReStructuredText is a revision and re-interpretation of the StructuredText and Setext lightweight markup systems.
The ReStructuredText markup competes with other plaintext markup like the native wiki markup used in MoinMoin.
Markup Differences
Although the goals of ReST and Wiki markup are similar, the markup looks different. The most important differences are:
Links: MoinMoin uses Camelcase; ReST uses an appended underscore.
italics, bold, monospace: MoinMoin uses '', ''' and {{{ ; ReST uses *, ** and ``.
Sectionheadings: MoinMoin uses a different number of equal signs = on same line as the heading; ReST uses a line of text with an underline-adornment made of non-alphanumeric characters like = _ - . ~ and more.
What markup looks more natural to you is simply a matter of taste. When working within a community wiki refuse the temptation to reformat from either markup into another, or people probably will become upset with you.
Using ReST in MoinMoin
The page HelpOnParsers/ReStructuredText contains more information about using ReST within MoinMoin wiki pages.
It is possible to make use of some MoinMoin macros (see HelpOnMacros) functionality from within ReStructuredText.
Links
reStructuredText -- Overview and more links.
http://docutils.sourceforge.net/docs/user/rst/quickstart.html -- A good introduction.
Docutils project homepage -- formerly known as Python Docstring Processing System.
http://docutils.sourceforge.net/docs/ref/rst/introduction.html#goals -- The goals.
See also BizarStructuredText for a description of another markup alternative.