Similar to SPYSEE

.co

Codecademy

CodePlex

Collaborative real-time editor

Common Gateway Interface

.coop

.cr

Craigslist

.cu

.cw

.cx

.cy

.cz

Data URI scheme

Datagram Congestion Control Protocol

Datagram Transport Layer Security

DAViCal

.de

DNS zone transfer

.do

.dz

.ec

Eduroam