[OSM-legal-talk] License Cut-over and critical mass

[Rob Myers]

On 07/24/2010 05:46 PM, Anthony wrote:
>
> But that would mean that mashing up CC-BY-SA data with ODbL data would
> violate CC-BY-SA.

Copyleft licences (or a copyleft licence and a hybrid copyright/DB 
Right/contract law conceptual approximation of sharealike) are 
*generally* mutually incompatible as they require derivative works to be 
placed under the same single licence.

You can however mash-up the produced work under BY-SA.

Creative Commons did put a mechanism in place with BY-SA 3.0 to declare 
other licences "compatible" with BY-SA and allow derivatives to be 
relicenced under them. But they haven't declared any compatible yet.

- Rob.