Terrorist groups use social media platforms, such as online forums and Facebook, as tools to indoctrinate, radicalise and recruit new members. Gabriel Weizmann carried out a study on the relationship between new media and terrorism and found that organised terror groups greatly use social media, with nearly 90% of terrorism taking place online. 
Social networking sites facilitate easy access to impressionable, and typically young, people who may be emotionally weak or experiencing mental health issues such as depression. What’s more, the social platforms also allow for their message to be disseminated to a global audience at the click of a button, and also provide terror groups with the possibility of engaging in constant real-time communication with their target audience.
For instance, the orchestrators of the Boston Marathon Bombing, the Tsarnaev brothers, were recruited through social media. FBI interrogators discovered that the brothers identified with extremist Islamic beliefs that had been developed through online material and messages. 
Through social platforms, terrorist groups not only interact with supporters and potential recruits but also other members of the public. The Islamic State of Iraq and The Levant (ISIS) have used social media to release disturbing and threatening material such as videos of beheadings. These videos can be viewed online by all internet users and are a medium through which the group attempts to instil fear in the public. 
So, social networking sites are not good for society as they are easily accessible and widely used. This combination means that those who seek to disrupt the life of citizens and wreak havoc upon the global population, such as terrorist groups, can easily do so and reach a wide audience as well. Social media is a tool through which they can not only radicalise people from all parts of the world but also share their violent acts on a global virtual stage.