From a SearchSecurity link to a DoS definition httpsearchappsecuritytechtargetcomsDefinitionsidgcihtml  On the Internet a denial of service DoS attack is an incident in which a user or organization is deprived of the services of a resource they would normally expect to have  Later clarification does not qualify that it is required for a webserver to stop responding for it to be a DoS only that typically this is the result  Despite what the group claims from the definition of DoS listed on Wiki and at this other security website AA commits a DoS when it causes the site to consume its resources such that it can no longer provide its intended service Obstruct the communication media and the criminal is deprived of the services of a resource they would normally expect to have  AA is not the law and it is not a web host  Therefore its actions are a form of vigilante action despite their belief it is for the greater good  Im not defending  perpetrators and I believe they should be shut down  However taking the law into your own hands is not something that should be suggested when there are legal channels otherwise