Share Alike (ShareAlike) is a Creative Commons copyright license type that is viral. At its basic level, it imposes nearly no additional restrictions. There are four different kinds of share-alike licenses from Creative Commons.
- Attribution ShareAlike (cc-by-sa)
- Attribution Non-commercial ShareAlike (cc-by-nc-sa)
- ShareAlike (cc-sa, only a 1.0 generation licence)
- Non-commercial ShareAlike (cc-nc-sa, only a 1.0 generation licence)
The Creative Commons share-alike licenses are not compatible with each other. There are also two generations of Creative Commons licences, 1.0 and 2.0. Works under version 1.0 license can't be used under the latter version of the license without the author's consent. However, works under 2.0 can be used under the future versions of the corresponding license.