Internet social networks are developing nowadays and provide almost unlimited possibilities for communication. On the other hand, architecture of social networks enables terrorists and criminals to use it for their purposes. Networks become a platform, where terrorist organizations recruit new members and exercise information-psychological impact. The analysis of the threats of destructive use of networks, results of the Russian-language social networks content analysis are presented in the article. The topic of the content analysis is the terrorist organization „The Islamic State of Iraq and Levant“, prohibited in Russia. On the base of results of the content analysis, the practical recommendations of how to minimize threats of harmful usage of social networks are developed.