[OSM-talk] Dual/Multiple licencing

[Tobias Knerr]

Brendan Morley wrote:
> Why must there be migration to the new licence?  Why can't we run both indefinitely?

A major reason for introducing ODbL is that many believe CC-by-SA to
only inadequately protect our data (so that it might be possible in some
jurisdictions to use our data without respecting attribution and
share-alike requirements). If we dual-license, someone with the
intention to take our data can simply pick the "weaker" license, so this
wouldn't help at all.

Adopting a dual-licensing scheme would also require us to remove data
added by contributors who don't agree to this change, just like
switching to ODbL (unless we want to create two different sets of data
and essentially fork the project, which imo is the least attractive
option of all).

And finally, it would become impossible to re-import modified
information from uncooperative users. In order to do this, we'd need
permission to distribute it under both licenses, but a user can of
course decide to only publish modifications under one of the two licenses.

Tobias Knerr