The Islamic State of Iraq and the Levant (Isis) is the first terrorist group whose members have grown up on the internet. They are exploiting the power of the web to create a jihadi threat with near-global reach. The challenge to governments and their intelligence agencies is huge – and it can only be met with greater co-operation from technology companies.

Terrorists have long made use of the internet. But Isis’s approach is different in two important areas. Where al-Qaeda and its affiliates saw the internet as a place to disseminate material anonymously or meet in “dark spaces”, Isis has embraced the web as a noisy channel in which to promote itself, intimidate people, and radicalise new recruits.

The extremists of Isis use messaging and social media services such as Twitter, Facebook and WhatsApp, and a language their peers understand. The videos they post of themselves attacking towns, firing weapons or detonating explosives have a self-conscious online gaming quality. Their use of the World Cup and Ebola hashtags to insert the Isis message into a wider news feed, and their ability to send 40,000 tweets a day during the advance on Mosul without triggering spam controls, illustrates their ease with new media. There is no need for today’s would-be jihadis to seek out restricted websites with secret passwords: they can follow other young people posting their adventures in Syria as they would anywhere else.