Anonymous rose into limelight in 2008 with a worldwide protest against the Church of Scientology for removing a video on YouTube featuring Tom Cruise. They declared war on the Church of Scientology for enforcing internet censorship, and soon launched a denial of service attacks against the church. Since then Anonymous has led dozens of similar attacks, all against what it saw as censorship.
Recent instances of hacking also reveal strong causes as motives. Anonymous hacked into the servers of ManTech International, a $2.6 billion computer security company that won a major F.B.I. contract and released the company’s internal company documents online taunting them saying “It’s really good to know that you guys are taking care of protecting the United States from so-called cyber threats.” Similarly, the hackers compromised McLean Va. Based Booz Allen Hamilton, a $5.6 billion company that does computer security work for the Defense Department, and released e-mail addresses of 90,000 military personnel on the public domain..

click to enlarge
In another instance, an executive at HBGary Federal made a public boast of his ability to unmask the members of Anonymous. The hackers retaliated by breaching the network of this very company, and releasing online a large trove of the company’s e-mail messages that included details of its business transactions. The release information disclosed a shady undercover operation to discredit WikiLeaks and people who support the group, and the company had to fire the CEO, to distance itself from the controversial plan.
On June 8 2011 LulzSec hacked into the National Health Service servers and gained access to health service passwords. They however issued a statement: “we mean you no harm and only want to help you fix your tech issues… we’re a somewhat known band of pirate-ninjas that go by LulzSec. Some time ago, we were traversing the internet for signs of enemy fleets. While you aren’t considered an enemy – your work is of course brilliant – we did stumble upon several of your admin passwords.” Soon after this,
Anonymous and its affiliated groups have also launched denial-of-service attacks on PayPal and MasterCard, to retaliate against processing donations for WikiLeaks, and against PBS.com in retaliation for an allegedly defamatory documentary on WikiLeaks source Bradley Manning.
In August 2011, Anonymous hacked into the BART website and publicized the names, addresses, personal e-mails and passwords of 102 Bay Area Rapid Transit System (BART) police officers, to take revenge against BART’s attempt to cut cell services.