  One of the Internet's greatest strengths is the degree to which it
facilitates access to any of its resources from users anywhere in the world.
However, users in the developing world have complained of websites blocking
their countries. We explore this phenomenon using a measurement study. With a
combination of automated page loads, manual checking, and traceroutes, we can
say, with high confidence, that some websites do block users from some regions.
We cannot say, with high confidence, why, or even based on what criteria, they
do so except for in some cases where the website states a reason. We do report
qualitative evidence that fears of abuse and the costs of serving requests to
some regions may play a role.
