The hacktivist group Anonymous has attacked the terrorist organization Islamic State (ISIS) on a large scale. ISIS has a very strong social media presence and in this attack, its numerous accounts were taken down. ISIS uses these accounts to spread its propaganda and recruit new members.

ISIS was believed to be responsible for the attack on the satirical magazine Charlie Hebdo of Paris and later al-Qaeda in the Arabian Peninsula (AQAP) took the responsibility. Apart from recruitment and publicity, ISIS uses its YouTube channel to share the videos of executions of prisoners.

In a YouTube video, the Hacktivist Group Anonymous and RedCult announced the #OpISIS operation and claimed to have gained control over many social media accounts (Facebook and Twitter) of the terrorist organization. The group mentions that this campaign is still going on and they aim to target more.
In this video, the following message is delivered by Hacktivist Group Anonymous, and ISIS is warned about more attacks to come in near future:

Greetings citizens of the world, we are Anonymous,
Operation ISIS Continues:
First we need to clarify few a things.
We Are: Muslims, Christians, Jews…
We Are hackers, crackers, Hacktivist, phishers, agents, spies, or just the guy from next door.
We Are students, administrators, workers, clerks, unemployed, rich, poor, We are young, or old, gay or straight.
We wear smart clothes or rugs, we are hedonists, ascetics, joy riders or activists.
We come from all races, countries, religions, and ethnicity.
UNITED AS ONE, DIVIDED BY ZERO…
We Are Anonymous.
-REMEMBER…THE TERRORISTS THAT ARE CALLING THEMSELVES ISLAMIC STATE,(ISIS), ARE NOT MUSLIMS!!!.

-ISIS; We will hunt you, Take down your sites, Accounts, Emails, and expose you…
From now on, no safe place for you online…
You will be treated like a virus, And we are the cure…
We Own The Internet…
We are Anonymous, We are Legion, We do not forgive, We do not forget, Expect us.
watch video here

https://www.youtube.com/watch?v=BPE_sRhZp6M#t=33

This Sunday, Anonymous published a huge list of more than a thousand media accounts, recruitment sites and e-mail addresses. See the whole list here.
http://fossbytes.com/hacktivist-group-anonymous-takes-isis-social-media-accounts-opisis/