Creative Commons by-sa

From the Quicksilver Metaweb.

Creative Commons by-sa is the usual name of the Creative Commons free documentation license that requires attribution - who the article is "by" and share-alike or "sa" terms. It is often considered equivalent to the GFDL and some projects (like Wikitravel use it instead of that license). However, the GFDL text corpus is distinct from the CCbysa corpus, and texts from the two cannot be mixed without permission of all attributed authors.

Also, the GFDL contains some moral rights terms regarding that are designed to prevent various repurposings of documents, or claiming rights to extensions of documents, that seem to be possible under CCbysa. Accordingly, negotiations are ongoing between Creative Commons and GNU regarding dual-licensing, which may lead to a variant of the CC-by-sa, which is acceptable to GNU as a strict equivalent of the GFDL. This may not happen soon, or ever.