I didn't spot anything particular naughty in BY-SA 4.0 with a quick glance. It looks like they have even removed some scary bits of BY-SA 3.0, such as the vague and potentially abusable "You must not distort, mutilate, modify or take other derogatory action..." clause. The license text is also much easier to read to mere mortals than in 3.0. Thus, my initial impression is mainly positive.
Before anyone asks, BY-SA 3.0 allows you to relicense derivative works under BY-SA 4.0. Likewise, BY-SA 4.0 will allow derivative works to be relicensed under future versions of BY-SA in the future.
To me, the biggest remaining question is whether the wise men at Debian will approve of the license or cast it in eternal damnation for the smallest imaginable reason.
Disclaimer: IANAL, and I didn't even read through the license text particularly carefully.
Posted: 26 Nov 2013, 20:26