Chainki - Built on a base of ODP data, invites visitors to add or edit sites using a wiki interface. Uses content in English and several other languages. - http://chainki.org/
Cses.us - Web directory using ODP data, with added advertising. - http://www.cses.us/
Cocaine Help - Site with information for cocaine recovery issues, using the ODP directory powered by PHPODP with Thumbshots. - http://www.cocainehelp.org/pnODP.html
ClixShare.com - Pay per click site uses ODP directory with Thumbshots. - http://www.clixshare.com
CMSinfo.dk - Directory using Thumbshots with ODP. - http://cmsinfo.dk
Compare Prices - Uses Shopping category of the ODP directory. - http://www.comparepricesdirectory.com/
Cne Fly - Site using ODP data. - http://www.cnefly.com/
Christseek - Uses the complete ODP Directory with Thumbshots, but uses the Christianity subcategory of Society as the starting point. - http://www.christseek.com/
Classifiedv - Directory based on the Open Directory data dumps. - http://directory.classifiedv.com/
ComicBookSites.com - Uses ODP data to help visitors find comic book related sites and resources. - http://www.comicbooksites.com/
Cape-horn.com - Travel directory for South America and Antarctica drawn from relevant categories in the ODP in English, Spanish and Portuguese. - http://www.cape-horn.com
The CADwire - Delivers CAD industry news. Includes a directory drawn from relevant sections of the ODP. - http://www.cadwire.net
CEOExpress - Portal using a webdirectory from the ODP (POD). - http://www.ceoexpress.com
Collect-Online - Uses parts of Recreation/Collecting and others. Live data. Anaconda. - http://collect-online.com/
The Cow Corral Search Engine - A demonstration from master.com of the search and directory it offers to webmasters, using the Open Directory data. - http://thecowcorral.master.com/
Cool4Kids.com - Using the ODP Kids and Teens directory. - http://www.cool4kids.com/