[Commons-l] [Foundation-l] [cc-licenses] Requirements for a strong copyleft license

[Daniel Kinzler]

Brianna Laugher wrote:
[...]
> That way, CC-BY-SA is strong copyleft as default (and that's surely
> the best thing for the growth of the commons -- all of them), and
> people who want to extend "weak copyleft" still can. And we don't get
> confusion caused be an extra official (CC) license.
> 
> For the good of the commons we need the default to be strong copyleft, no?

The only problem with that is: we we have "strong" copyleft CC-BY-SA, and follow
it to the letter, CC-BY-SA image can not be used in GFDL articles. All pages on
Wikipedia that use CC-BY-SA images would have to be relicense with the consent
of all contributors. So, such a strengthening would be very harmful, unless
combined with a GFDL compatibility clause.

-- Daniel