ISIS on the Cutting Edge--In Savagery AND Tech-Savviness

As this Fortune piece notes, both have been essential as ISIS builds its "brand":

ISIS has built its strategy using a sharply differentiated and compelling vision of the endgame: a return to the glory days of a Caliphate. En route, it acquires early customers with offers of very basic services in the territories it occupies. Its funding for each new phase is secured by its earlier phases of growth — through extortion, selling electricity and oil from captured power plants and occupied oil fields. ISIS brand-building and recruiting strategy applies lean startup methods that reach global audiences at low cost using a mix of media, including horrific videos, e-magazines and state-of-the-art digital direct mail tactics, replete with over 46,000 affiliated Twitter accounts, with an average of a thousand followers apiece along with smartphone apps. 

A Medieval, supremacist mindset backed up by the latest high-tech gadgetry--now, that's a terrifying combo.