Change.org, an online human rights activist organization, is complaining that it is the victim of cyber-attacks from China aiming to bring the site down to stop readers from signing a petition demanding the release of artist Ai Weiwei. Ai, one of China's most famous artists, was detained on April 3 in Beijing as he was about to board an airplane for Hong Kong. His whereabouts have been undetermined since. Although Chinese news sites have indicated he would be charged with economic crimes, his arrest is universally assumed to be because of protests he has led over substandard construction that left 5,000 children dead in an earthquake two years ago, among other issues.