"JN" here stands for "Jabhat al-Nusra", an al-Qaeda-affiliated organization operating in Syria.
Warning, contains actual ISIS videos. Avoid if you don't want to end up on a watch list.
You don't have to watch them. The article itself is a fascinating read.
For those who want to read more, Thomas Rid's badly named "War 2.0" discusses the impressive media efforts of groups such as Hamas (who have their own satellite TV channel).