“Boko Haram, the radical Islamic sect that controls parts of Nigeria,
became the largest affiliate of the Islamic State in March, after months
of strengthening its media presence and courting the jihadist group.”

“Boko Haram’s few early videos were of low quality and were disseminated haphazardly. They featured the erratic behavior of the group’s leader, Abubakar Shekau, and were so badly edited that at least one rival jihadist group used a clip from a Boko Haram video to mock Mr. Shekau.”

“After the Islamic State announced its goal to build a caliphate, Mr. Shekau actively expressed support for Islamic State leadership. In July 2014, Boko Haram began adding the Islamic State’s flag and signature Islamic chant to its videos.”

“A month later, Mr. Shekau described territory Boko Haram had recently seized as a dawla, or a state, of Islam. Jacob Zenn, an analyst at The Jamestown Foundation, says this phrase was a clear reference to the Islamic State, which is also known as ISIS.”

http://www.nytimes.com/interactive/2015/06/11/world/africa/boko-haram-isis-propaganda-video-nigeria.html