Wikileaks isn't the best-loved website in the world right now. Anyone associated with the leak page and its crusade against everyone are coming under harsh scrutiny. And that includes Anonymous, the Internet's blind, vicious animal brain.
As a response to the near-global censure of Wikileaks, Anonymous launched D-DOS attacks at Amazon, PayPal, MasterCard, Visa and a PostFinance, a Swiss bank. MasterCard and Visa both went down under the strain. The website for the Swedish prosecutor going after Assange was also downed in a hail of bots.
Government response has been swift and terrible. The FBI executed 40+ search warrants on members of Anonymous this week. At the same time, 5 members of Anonymous were arrested in the UK for the same attacks.
This isn't the first time members of Anonymous have run afoul of the law. Back in 2008, a number of them were arrested in the flesh at a protest in Atlanta. Alex Tapanaris, may have been arrested in Greece (but claims it didn't happen), while two teenagers in the Netherlands were arrested for the pro-Wikileaks attacks last December.
At this point, it is fully clear that "Anonymous" can't (or never could) rely on anonymity from the entities they strike. So far, the mass of users are protected by sheer numbers and their relatively low level on the "collaboration" flagpole. But arrests like these may have a chilling effect on the people who put the most effort into organizing and executing these mass attacks.