OperationIce ISIS took place in 2015. On June 21, 2014, a video was posted to YouTube, but the operation officially took place sometime in 2015. The video was posted on the channel TheAnonMessage, and it was Anonymous declaring a cyber-war on the infamous, worldwide, terrorist organization known as ISIS.
The war was stepped up after each of the murderous attacks in Paris. Anonymous released a statement to ISIS, "You are vermin, expect many cyberattacks after Paris!" 
This operation has achieved some success.