The American government is taking credit for the recent decline in ISIL (Islamic State in Iraq and the Levant) activity in social media. On Twitter, for example, messages supporting or mentioning ISIL are about half as numerous now as they were two years ago. There is a lot more anti-ISIL commentary and traffic among Arab speaking Internet users. While some of this decline in pro-ISIL activity is due to public opinion turning against ISIL because of their continued attacks on Moslem women and children and any Moslem who does not agree with them there were other trends developing as well. For example Western governments have learned (often by trial and error) how to use the law, popular attitudes among Moslems towards Islamic terrorism and some commonly used Internet marketing and publicity techniques against Islamic terror groups. All these efforts have been underway for years and have reported much progress since 2015.
A lot the basic work was done by U.S. SOCOM (Special Operations Command) which pioneered the use on commercial technology to gain an edge as Islamic terrorists have moved a lot of the combat to the Internet. There Islamic terrorists did a lot of their recruiting, fund raising, training and carrying out attacks or discussing tactics in general. SOCOM used commercial Internet marketing software systems to better (and more quickly) analyze what Islamic terrorists were doing on the Internet. This is nothing new for SOCOM, which has been informally using social networking sites and Internet activity in general to find, monitor and sometimes manipulate terrorist suspects. This has been going on since the late 1990s but as time went on SOCOM found that formal and analytic techniques produced better results.
The U.S. Army Special Forces has one of the largest collections of experienced counter-terrorism operators who know the culture and languages of areas where there is a lot of Islamic terrorist activity. These soldiers have spent years learning about cultures and languages and honed that knowledge by actually operating in those areas. This is now being used to develop rapid analysis of Internet data (discussion topics, direction of discussions, traffic analysis) and quickly determine how best to respond. Many people do not realize that SOCOM had always had lots of psychological war specialists and these specialists set up message centers staffed with locals who can start posting new types of messages in response to detected trends. What SOCOM was seeking was ways to derail Islamic terrorists propaganda (especially the ones involving mass murder or beheadings of civilians) and capitalizing on it to mobilize local (where the Islamic terrorists operate) public opinion against these atrocities. This played a major role in developing anti-ISIL Internet messages that resonated with Moslem audiences ISIL was depending on.
By playing up the extent of harm ISIL was doing to Moslem children and Moslem culture in general the West finally had an anti-ISIL message that could not be dismissed as “Western propaganda.” That was largely because of the use of people literate in Arabic and other languages popular with many Islamic terrorists in Africa, Afghanistan, Pakistan and Southeast Asia to get on pro-terrorist message boards and post messages designed to weaken the ISIL propaganda.
Finally the government has taken better advantage of laws in many countries that forbid the kind of “kill, kill, kill” message ISIL regularly uses. ISIL turned out to be very vulnerable here because there was ample evidence, often posted to the web by ISIL, that the vile ISIL message was not idle chatter but deadly serious and therefore illegal and subject to bans on ISIL using social media in many countries.
Another technique used has been around for over a decade. Social networking sites and Internet activity has long been a major source of information for intelligence and police agencies. There is an irony in this because sites like Facebook, Snapchat and Twitter are also hailed as catalysts for revolution and social change. While that's true, these sites have also been a big help to those seeking to detect and prevent criminal behavior. This can have fatal consequences in dictatorships, where the police and intel groups can use data gathering and analysis tools (developed for marketing via the Internet) to find people who are protesting or rebelling against the government. Even if these Facebook users are using codes and pseudonyms to remain hidden, the scanning and analysis tools can often uncover them. Twitter traffic can also be analyzed for useful information on who is doing what and where they are. Social networking sites are thus a double edged sword. They can be used to organize, inform, and mobilize large groups. But in doing this you provide the secret police a lot of information you would rather not share with them. Islamic terror groups advise their members to avoid social networking sites, but that has proved hard to enforce. Social networking was designed to be alluring, as well as useful, especially to niche groups.