Anonymous is a famous large group of hackavists whom successfully broke into a number of corporations and police servers. As well as disabling government security sites, stole sensitive information such as credit card details, and defaced commercial websites.
fro 2008 to 2012 was when the group dubbed “Operation Tunisia”, which involved recruiting a number of Tunisian hackers to help take down eight government websites using DDoS (Distributed Denial of Service Attacks) attacks in support of Arab Spring movements in 2010.
What makes these activities different from your usual hacker. Is that they are not done for financial gain but rather to express opposition against Internet censorship and control. They acts as activists through their hacking , with the aim to express and stand for what they believe in.
Activism in the context of art and media 