Everything is possible, as we are not even in the design phase
It would also be possible to give different licenses to different properties of the data! An example:
- location, address, name and description are PD (for use in OSM)
- contact person data are CC-BY-SA-NC and are stored elsewhere
- Photo is CC-BY
A website will gather this data from different websites, and can display the appropriate License for each property besides it in a popup.
In this scenario we wouldn't clutter up the map with thousands of contributor names, as the data displayed in the overview is ODbL (OSM), and the details can be displayed with their respective license.
I love that idea