Online Library

The Internet and, in particular, Online Social Networks have changed the way that terrorist and extremist groups can influence and radicalise individuals. Recent reports show that the mode of operation of these groups starts by exposing a wide audience to extremist material online, before migrating them to less open online platforms for further radicalization. Thus, identifying radical content online is crucial to limit the reach and spread of the extremist narrative. In this paper, our aim is to identify measures to automatically detect radical content in social media. We identify several signals, including textual, psychological and behavioural, that together allow for the classification of radical messages. Our contribution is threefold: (1) we analyze propaganda material published by extremist groups and create a contextual text-based model of radical content, (2) we build a model of psychological properties inferred from these material, and (3) we evaluate these models on Twitter to determine the extent to which it is possible to automatically identify online radical tweets. Our results show that radical users do exhibit distinguishable textual, psychological, and behavioural properties. We find that the psychological properties are among the most distinguishing features. Additionally, our results show that textual models using vector embedding features significantly improves the detection over TF-IDF features. We validate our approach on two experiments achieving high accuracy. Our findings can be utilized as signals for detecting online radicalization activities.

In this paper we use methods of social network analysis to examine the inter-organizational structure of the white supremacist movement. Treating links between Internet websites as ties of affinity, communication, or potential coordination, we investigate the structural properties of connections among white supremacist groups. White supremacism appears to be a relatively decentralized movement with multiple centers of influence, but without sharp cleavages between factions. Interorganizational links are stronger among groups with a special interest in mutual affirmation of their intellectual legitimacy (Holocaust revisionists) or cultural identity (racist skinheads) and weaker among groups that compete for members (political parties) or customers (commercial enterprises). The network is relatively isolated from both mainstream conservatives and other extremist groups. Christian Identity theology appears ineffective as a unifying creed of the movement, while Nazi sympathies are pervasive. Recruitment is facilitated by links between youth and adult organizations and by the propaganda efforts of more covertly racist groups. Links connect groups in many countries, suggesting the potential of the Internet to facilitate a whitesupremacist “cyber-community” that transcends regional and national boundaries.