How can twitter help fight terrorism?

Who would have thought that five years ago when we started using Facebook, Twitter and other early forms of social media that today, these platforms could offer some of the most effective tools to combat terrorism. But how, you might ask? 
As pupils in an all-girls school in a relatively affluent area of Western Europe, security in school is not something that I believe many parents will worry about.  Once we've avoided the traffic and walked through the school doors, I'm sure we all feel relatively safe in our school environment. 
However, for many years in certain countries, pupils have not been able to take this for granted. Whether it is driven by the gun culture in the USA or more recently in countries like Nigeria, many pupils do not enjoy this level of safety. 
As you will now be aware, over two months ago a terrorist gang kidnapped more than 200 Nigerian schoolgirls. Perhaps the most shocking thing about this is that this event was, initially, not particularly newsworthy because events of this nature happen with such regularity. 
But this is where social media really came into its own, fighting terrorism with a hashtag campaign #BringBackOurGirls which very quickly brought this to the attention of people in all corners of the world.
Soon, politicians from other countries saw the opportunity to align themselves with helping this campaign and pressure was brought to bear on the Nigerian government who, before then, had been very slow to react. Suddenly the Boko Haram terrorist group had an unexpected enemy in the form of hundreds of thousands of social media users. 
In isolation, it's clear that this army of social media users is not enough to win the war. However this campaign demonstrates how successful social media can be in mobilising ordinary people who can make a real difference by making those in power sit up and take notice.
In the case of the Nigerian schoolgirls, let us all hope that this campaign, and the use of social media, is not too late to bring about action that will find them and bring them home to their distraught parents.