CKAN is the Comprehensive Knowledge Archive Network, a registry of open knowledge packages and projects (and a few closed ones).
CKAN makes it easy to find, share and reuse open content and data, especially in ways that are machine automatable.
As a system CKAN functions as a synthesis of several different services:
As the diagram shows, CKAN combines the features of a listing/registry, a package index and a wiki. As a registry it acts like freshmeat but for open data and content resources. However it adds to a simple registry in key ways.
First, thanks to its underlying versioned domain model CKAN has a wiki-like interface that lets anyone add and material held in it. Second, and unlike a wiki, CKAN can store 'structured' information, which allows it to provide 'index'-like features such as automated registration, discovery and installation of material. In this respect it behaves like CPAN or PyPI in the software world -- though again for open data and content not code.
More about CKAN, and the background to its creation can be found in these slides.
In addition to use of this website, ${g.site_title} data can be viewed and changed by using CKAN's Application Programming Interface (API).
The API takes the form of a RESTful (Representational State Transfer) style API for accessing CKAN database objects and a Search API.
For full details of accessing the API, see the documentation at: http://knowledgeforge.net/ckan/doc/ckan/api.html
The CKAN software and site is developed and maintained by the Open Knowledge Foundation. Both the CKAN code and data are open: free for anyone to use and reuse. To find out more check out the the CKAN project page on the Open Knowledge Foundation site.
Various people and projects have contributed to the development of CKAN including: