The present article contends that terrorist activism on the Internet is determined by the technical configuration and ease of use of the tool. Engagement in Internet activities considered criminal offenses is not only explained by a progression in the level of radicalization of the individual. Rather, the type of barriers to entry which they must overcome plays a decisive role in the decision. The article classifies the various Internet spaces featuring terrorist content under the categories of “hard platforms” and “friendly platforms”. This differentiation will enable us to identify how the barriers to entry to such activism have evolved over the last two decades and how this evolution has been responsible for different levels of terrorist mobilization in cyberspace. The investigation focuses on jihadist terrorism and uses the antiterrorist operations carried out in Spain during the period 2001-2020 as a case study.