5. YouTube Porn Day

Date: January 6, 2010 
Victim: YouTube  

In reponse to YouTube suspending the account of an Anonymous member who uploaded music videos to his channel, Anonymous encouraged all of its users to create fake user accounts, create videos containg a mixture of porn and safe-for-work images, and upload them to YouTube under friendly names. There's no telling how successful the attack was, but the BBC reported that one 12-year-old who viewed one of the videos and responded: "I'm 12 years old and what is this?"