  Despite the high perceived value and increasing severity of online
information controls, a data-driven understanding of the phenomenon has
remained elusive. In this paper, we consider two design points in the space of
Internet censorship measurement with particular emphasis on how they address
the challenges of locating vantage points, choosing content to test, and
analyzing results. We discuss the trade offs of decisions made by each platform
and show how the resulting data provides complementary views of global
censorship. Finally, we discuss lessons learned and open challenges discovered
through our experiences.
