Human life progress has successfully defined multiple epochs’ evolution with specific peculiarities. Today we live in the modern digital era, numerous computer devices, services and networks are actually significant. At the same time, these new science and technology achievements are rated both as good and bad for their users. The digital progress is however visible and of utility for terrorist organizations. This article focuses on selected illustrations of Internet technologies used by terrorist organizations. Special discussion emphases are given to uses towards (i) terrorist organizations radicalization of young people; (ii) spreading propaganda; (iii) internal communication, training, planning, coordination and committing terrorist acts.