The Saudis, who most likely control ISIL, are Wahabists.
The two are pretty close in attitudes. I need to find the page in Allen's ‘God's Terrorists’ that describes the major doctrinal points of Wahabism. It just struck me as so much how ISIL’s members are behaving. They have the elan of true believers and are obviously striking terror into the hearts of other Muslims. This is a violent redemptionist movement and ISIL reminds one of the Sudanese Mahdists from the 1880’s.
ISIS/ISIL is officially Salafi. To put is rather simply: “Salaf” is a reference to ‘the pious predecessors’. Wahabi, refers to people who follow the teachings of abdul Wahab, a teacher who was once thrown out of Iraq for heretical teachings, but who gained popularity with the tribal masses in Saudi Arabia. The term ‘Wahabi’ is said to be somewhat derogatory since it refers to a single person not ‘the pious predecessors’ ie the first 3 generations of Islam, collectively.