Twitter, it seems, may have been trying to shut them down. According to tweets, accounts named @Anon_Operation and @AnonOperation went down yesterday. (“Anonymous” is the name of the underground organization leading the DDoS attacks.) They currently appear to be back up. New accounts have emerged to replace them, including variations on their spelling, like @Anon_Operations and @Anon_Operationn, as well as ones with names like @Op_Payback and @AnonOpsNet.