Creative Commons: http://www.creativecommons.org/
CSS (cascading style sheets): http://www.w3.org/Style/CSS/
CTAN (Comprehensive TeX Archive Network): http://www.ctan.org
Culture.fr: http://www.culture.fr/
Cursus (EBSI): http://www.ebsi.umontreal.ca/cursus/
CyLibris (éditions): http://www.cylibris.com/
Digital Broadcast: http://www.worlddab.org/
DailyLit: http://www.dailylit.com/
Daily Yomiuri On-Line: http://www.yomiuri.co.jp/dy/
DAISY (digital accessible information system) Consortium: http://www.daisy.org/