BY-SA and GPL: creativecommons closed the chasm in the sharealike/copyleft community

This is the biggest news item [1] for free culture and free software in the past 5 years: The creativecommons attribution sharealike license is now one-way compatible to the GPL — see the message from creativecommons [2] and from the Free Software Foundation [3].

• Blender [4] rigs under cc by-sa which use libraries under GPL are safe against suing, even if a Blender code contributor goes crazy,
• 3D models like the self replicating 3D printer RepRap [5] and libre hardware designs under cc by-sa and GPL can be combined,
• GPL-compatible Free Software can utilize all content from the Wikipedia [6] and
• On the personal side: we can merge art from Ryzom [7] and Battle for Wesnoth [8] and use both in the Pirate Party RPG [9].

Some license compatibility legalese might sound small, but the impact of this is hard to overestimate.

(I’ll now revise some of my texts about licensing — CC BY-SA got a major boost in utility because it not longer excludes usage in copyleft documents which need the source to have a defended sharealike clause)