  Research shows that various social media platforms on Internet such as
Twitter, Tumblr (micro-blogging websites), Facebook (a popular social
networking website), YouTube (largest video sharing and hosting website), Blogs
and discussion forums are being misused by extremist groups for spreading their
beliefs and ideologies, promoting radicalization, recruiting members and
creating online virtual communities sharing a common agenda. Popular
microblogging websites such as Twitter are being used as a real-time platform
for information sharing and communication during planning and mobilization if
civil unrest related events. Applying social media intelligence for predicting
and identifying online radicalization and civil unrest oriented threats is an
area that has attracted several researchers' attention over past 10 years.
There are several algorithms, techniques and tools that have been proposed in
existing literature to counter and combat cyber-extremism and predicting
protest related events in much advance. In this paper, we conduct a literature
review of all these existing techniques and do a comprehensive analysis to
understand state-of-the-art, trends and research gaps. We present a one class
classification approach to collect scholarly articles targeting the topics and
subtopics of our research scope. We perform characterization, classification
and an in-depth meta analysis meta-anlaysis of about 100 conference and journal
papers to gain a better understanding of existing literature.
