Excerpt from this article:
Wikimedia and Facebook have given Angolans free access to their websites, but not to the rest of the internet. So, naturally, Angolans have started hiding pirated movies and music in Wikipedia articles and linking to them on closed Facebook groups, creating a totally free and clandestine file sharing network in a country where mobile internet data is extremely expensive.
It’s an undeniably creative use of two services that were designed to give people in the developing world some access to the internet. But now that Angolans are causing headaches for Wikipedia editors and the Wikimedia Foundation, no one is sure what to do about it.