In this report, we have sought to understand how violent extremists behave across an increasingly complex online ecosystem and consider the implications for how online violent extremism (VE) activity can be countered. We interrogated the variety of measures, behaviours and technology platforms that are being used by violent extremists internationally. In so doing, we identified gaps in understanding of the complex and expansive contours of the VE online landscape, and the extent to which VE online does, or does not, constitute a distinctive phenomenon that might require a different policy setting. The outcomes of the research will contribute to the undertakings of the Office of the Ambassador for Counter-Terrorism in establishing a first-rate network between Australia and its international partners that enables a ready and trusted exchange of knowledge and communication on VE and terrorism activities to maximise the effectiveness of counters.