[OSM-legal-talk] Would The ODbL and BY-SA Clash In A Database Extracted From a BY-SA Produced Work?

[Rob Myers]

Some time ago the question was raised of what happens if you extract 
data from an ODbL produced work that is under BY-SA.

The concern was that the resulting database would cause a conflict 
between the ODbL and BY-SA as it would be a derivative both of the ODbL 
database and of the BY-SA produced work, thereby triggering both 
licences' mutually incompatible share-alike clauses.

I asked about this on the odc-discuss list. The answer is informative 
and I recommend reading it in full:

http://lists.okfn.org/pipermail/odc-discuss/2010-August/000291.html

My understanding of the answer is that the data isn't what you are 
licencing under BY-SA. You are licencing the originality/creativity 
involved in making the produced work. So when you extract the data, you 
have not extracted anything that is covered by BY-SA. Any database you 
create as a result is therefore not covered by BY-SA, so the ODbL 
applies without clashing. And the user knows this because of the ODbL 
advertisement attached to the BY-SA work.

This is elegant but it took me a while to get my head around it. :-)

- Rob.