Twitter has suspended the account of the Anon "Operation Payback" team @Anon_Operation. This account was being used by the Anon team to send out messages on when they were going to hack which site.
Twitter was one of the targets for Anon to attack, because they thought they were censoring Wikileaks content from the trending topics. However, Twitter has denied those claims, but the suspension of the "Operation Payback" account could enrage the members of Anon who might possibly DDoS Twitter.
Start bracing yourself for some Twitter downtime.
Update: Operation Payback is now back on Twitter as @Anon_Operationn
Update 2: The original @Anon_Operation account is now back up. There was a tweet from the account which said that the deletion was accidental.