The use of free content on Wikipedia:

• Wikipedia:Wikipedia is free content - an explanation of the third pillar of Wikipedia
• Wikipedia:Copyrights – Wikipedia policy about copyright issues
• Wikipedia:Public domain – guideline about how the public domain applies to Wikipedia
• Wikipedia:Adding open license text to Wikipedia - about how to use free content from other sources within Wikipedia
• Wikipedia:The Free Encyclopedia – essay about how copyleft is used to provide a collaboration framework for Wikipedia
• Wikipedia:WikiProject Images and Media/Free – Wikiproject with the aim of spreading the use of free images in Wikipedia