While terrorism informatics research has examined the technical composition of extremist media, there is less work examining the content and intent behind such media. We propose that the arguments and issues presented in extremist media provide insights into authors’ intent, which in turn may provide an evidence-base for detecting and assessing risk. We explore this possibility by applying two quantitative text-analysis methods to 50 online texts that incite violence as a result of the 2008/2009 Israeli military action in Gaza and the West Bank territories. The first method—a content coding system that identifies the occurrence of persuasive devices—revealed a predominance of moral proof arguments within the texts, and evidence for distinguishable ‘profiles’ of persuasion use across different authors and different group affiliations. The second method—a corpus-linguistic technique that identifies the core concepts and narratives that authors use—confirmed the use of moral proof to create an in-group/out-group divide, while also demonstrating a movement from general expressions of discontent to more direct audience-orientated expressions of violence as conflict heightened. We conclude that multi-method analyses are a valuable approach to building both an evidence-based understanding of terrorist media use and a valid set of applications within terrorist informatics.