  On the worldwide web, not only are webpages connected but source code is too.
Software development is becoming more accessible to everyone and the licensing
for software remains complicated. We need to know if software licenses are
being maintained properly throughout their reuse and evolution. This motivated
the development of the Sourcerer's Apprentice, a webservice that helps track
clone relicensing, because software typically employ software licenses to
describe how their software may be used and adapted. But most developers do not
have the legal expertise to sort out license conflicts. In this paper we put
the Apprentice to work on empirical studies that demonstrate there is much
sharing between StackOverflow code and Python modules and Python documentation
that violates the licensing of the original Python modules and documentation:
software snippets shared through StackOverflow are often being relicensed
improperly to CC-BY-SA 3.0 without maintaining the appropriate attribution. We
show that many snippets on StackOverflow are inappropriately relicensed by
StackOverflow users, jeopardizing the status of the software built by companies
and developers who reuse StackOverflow snippets.
