Below, I have described a case example:
A chemistry web site allows users to search on chemical compounds in order to find other similar chemicals. The chemical similarity is determined based on the molecular structures. Molecular structure data is mined from Wikipedia data dumps. Users are not given the molecular structure itself.
The work of collecting chemical structure data is performed by Wikipedia editors. However, this data is disorganized, and it is neither acquired nor viewed by end users. End users only see data that has been transformed, and, as such, it is not found on Wikipedia. Does the web site present information that the Wikipedia licensor has rights to under regional laws?