Telegram has blocked around 78 ISIS-affiliated channels that the terrorists used to use. Telegram creators said they are carefully reviewing all user-submitted reports sent to them and are taking appropriate action to block such channels that are used to spread terror-related contents. There are still more than 100 other ISIS Telegram channels and thousands of Twitter and Facebook accounts affiliated with ISIS and each followed by thousands of Jihadists. The terrorist groups affiliated with the Islamic State have an extensive presence not only on social media accounts but also on popular end-to-end encrypted messaging app.
Source: https://thehackernews.com/2015/11/telegram-isis-channels.html