Bold options:

{{{
*bold*
**bold**
__bold__
'''bold'''
}}}

Italic options:

{{{
/italics/
//italics//
_italics_
''italics''
}}}


A star (*) is the most used symbol to bold text online. A slash (/) looks like slanted italics, so it is intuitive and thus easier to remember.  Double symbols are generally used in Creole to avoid accidentally parsing text not meant to be parsed.

The underscore (_) was not chosen, because that could be confused for underlining.

The double single quote ({{{''}}}) and triple single quote ({{{'''}}}) were not chosen, because they could be confused for a regular quotemark (") and is not clear that it is for emphasis.  Also, having to use quintuple quotes ({{{'''''}}}) to open and close bold italics gets really confusing.

== Bold in other wiki engines ==

[{PieChartPlugin title='Bold in wiki engines'

Triple single quote (23), 23
Double asterisk (15), 15
Single asterisk (15), 15
Double underscore (5), 5
Double single quotes (2), 2
Single underscore (2), 2

}]

(23) Triple single quote: FlexWiki, Friki, IkeWiki, JAMWiki, MediaWiki, miniWiki, MoinMoin, MoniWiki, Oddmuse, PmWiki, ProjectForum, ProWiki, ScrewTurn Wiki, SubWiki, TracWiki, UseMod, VQWiki, Wala Wiki, WikiASP, WikiDoc, WikiSH, WikyBlog, wxWikiServer

(15) Double asterisk: DokuWiki, Erfurtwiki, GeboGebo, Midgard Wiki, Oddmuse, OpenWikiNG, PBwiki, ProntoWiki, Qwik, UniWakka, WackoWiki, Wikepage, Wikidot, Wikispaces, WikkaWiki

(15) Single asterisk: Clearspace, Confluence, DidiWiki, FlexWiki, Instiki, KWikiKWiki, LunaWiki, MicKI, Netcipia, Oddmuse, PhpWiki, SocialText, StikiPad, TWiki, yawiki

(5) Double underscore: JSPWiki, SnipSnap, TikiWiki, Vanilla, Wiclear

(2) Double single quotes: PukiWiki, TiddlyWiki

(2) Single underscore: KeheiWiki, XWiki

See also [[WikiCharacterMarkupUsage]] for collision analysis for bold. There are no collisions (in the 26 Wikis analysed) for bold. That is there are no cases where {{{**}}} is used for something other than bold.

== Italics in other wiki engines ==

(30) Double single quote: ErfurtWiki, FlexWiki, Friki, IkeWiki, JAMWiki, JSPWiki, MediaWiki, miniWiki, MoinMoin, MoniWiki, Oddmuse, PBwiki, PmWiki, ProjectForum, ProntoWiki, ProWiki, ScrewTurn Wiki, SubWiki, TikiWiki, TracWiki, UseMod, VQWiki, Wala Wiki, Wiclear, Wikepage, WikiASP, WikiDoc, WikiSH, WikyBlog, wxWikiServer

(12) Double slash: DokuWiki, GeboGebo, Giki, Oddmuse, OpenWikiNG, Qwik, TiddlyWiki, UniWakka, WackoWiki, Wikidot, Wikispaces, WikkaWiki

(8) Single underscore: Confluence, Instiki, MicKI, Midgard Wiki, PhpWiki, Socialtext, StikiPad, TWiki

(4) Single slash: DidiWiki, KWikiKWiki, LunaWiki, Oddmuse

(2) Double tilde: Netcipia, SnipSnap

See also [[WikiCharacterMarkupUsage]] for collision analysis for italic. There are no collisions (in the 26 Wikis analysed) for italic. That is there are no cases where {{{//}}} is used for something other than italic.