Protesting Internet Censorship Operation Titstorm

They are protesting against forthcoming internet filtering legislation and the perceived censorship in pornography of small-breasted women (who are thought to be under age) and female ejaculation.

Source:
http://www.smh.com.au/technology/technology-news/operation-titstorm-hackers-bring-down-government-websites-20100210-nqku.html