Creative Commons is a non-profit organization that provides free tools that let authors, scientists, artists, and educators easily mark their creative work with the freedoms they want it to carry. Creative commons offers a set of licenses with differing freedoms for use by authors.
You can find complete information on the official Creative Commons Organization website.
Creative commons licences in OpenStreetMap projects
OpenStreetMap changed its licensing conditions on 12 September 2012 for its published data created and modified by its community:
- Any data uploaded and published before then were (and are remaining) licensed under Creative Commons - Attribution - Share alike 2.0 (CC-BY-SA 2.0). A read-only archive of this data has been kept for all data present before the switch and is still accessible.
- After that date, all OSM data are licensed under Open Data License (ODbL) and older OSM data that were not explicitly dual licensed under ODbL by their authors have been forcibly deleted from the published live database.
However, maps rendered from OpenStreetMap data (and from which no data can be directly derived mechanically, such as bitmap tiles rendered with Mapnik) can remain being published under CC-BY-SA (with the required attribution).
As well, contents in this OpenStreetMap documentation wiki are still published by default under CC-BY-SA 2.0 (except for images/files which have their own license indicated on their associated description page; some images/files may be possibly transcluded on this wiki from Wikimedia Commons, from which their respective description page is also transcluded to display their original description, attribution and licensing information).