Razib is beginning a series of posts at GNXP to analyze the intersection of Islam with terrorist organizations. His first post is a review of Marc Sageman's book, Understanding Terror Networks, including a tabulated summary of the relevant demographics. There's a healthy debate in his comment thread as well, where Razib clarifies that the Sageman's analysis is not addressing the global sympathy towards islamofascism, but rather the "the few hundred that have actually actively engaged in jihad against the far enemy of in the dar-al-harb." In other words, the people who are the actual and direct threat, not a broader and circular attempt at defining a self-serving clash of civilizations narrative.
The main question that this debate is trying to address is whether terror arises from socioeconomic roots or not. I think that this is a valid route of inquiry, but not one that will bear much fruit. The real root of terror is not grinding physical oppression, but rather the intellectual oppression that the jihadis universally relate as their motivators - partly imposed as a legacy of the post-colonial world, but also one imposed upon themselves from within, borne of seeing the world with the adopted mantle of vicimization. The focus is presently on Islam, but I think that we are speaking about something far more intrinsic to the human condition.