This is a list of the most commonly used wiki markup in support articles. For more complete documentation see:

Description	What it looks like	Wiki Syntax
Bold text	bold	`'''bold'''`
Link to another article	Name of article	`[[Name of article]]`
Link specific text to another article	click here	`[[Name of article\|click here]]`
Link to another site	http://www.mozilla.org	`[http://www.mozilla.org]`
Link specific text to another site	Mozilla	`[http://www.mozilla.org Mozilla]`
Numbered list	Item 1 Item 2 Item 3	`# Item 1 # Item 2 # Item 3`
Unordered list	Item A Item B Item C	`* Item A * Item B * Item C`
Unordered sub-list within a numbered list	Item 1 Item 2 Item 2a Item 2b Item 3	`#Item 1 #Item 2 #* Item 2a #*Item 2b #Item 3`
Table of Contents	Table of Contents (list of article headings)	`__TOC__`
Indicates a level 1 heading	Level 1	`= Level 1 =`
Indicates a level 2 heading	Level 2	`== Level 2 ==`
Image		[[Image:`Name of image`]]
Note	Note: Text	`{note}'''Note:''' Text{/note}`
Warning	Warning: Text	`{warning}'''Warning:''' Text{/warning}`
Keyboard shortcut	Ctrl + T	`{key Ctrl+T}`
Button	Button	`{button Button}`

Firefox

Markup cheat sheet