{ "rules_notify_users_about_new_comment" : {
    "LABEL" : "Notify users about new comment",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules", "rules_conditional", "comment" ],
    "ON" : { "comment_insert" : [] },
    "DO" : [
      { "variable_add" : {
          "USING" : { "type" : "listu003Cuseru003E" },
          "PROVIDE" : { "variable_added" : { "users_to_notify" : "Users to notify" } }
        }
      },
      { "LOOP" : {
          "USING" : { "list" : [ "comment:node:comments" ] },
          "ITEM" : { "current_comment_item" : "Current comment item" },
          "DO" : [
            { "CONDITIONAL" : [
                {
                  "IF" : { "NOT data_is" : {
                      "data" : [ "current-comment-item:author" ],
                      "value" : [ "comment:author" ]
                    }
                  },
                  "DO" : [
                    { "list_add" : {
                        "list" : [ "users-to-notify" ],
                        "item" : [ "current-comment-item:author" ],
                        "unique" : "1"
                      }
                    }
                  ]
                }
              ]
            }
          ]
        }
      },
      { "CONDITIONAL" : [
          {
            "IF" : { "NOT data_is" : { "data" : [ "comment:author" ], "value" : [ "comment:node:author" ] } },
            "DO" : [
              { "list_add" : {
                  "list" : [ "users-to-notify" ],
                  "item" : [ "comment:node:author" ],
                  "unique" : "1"
                }
              }
            ]
          }
        ]
      },
      { "LOOP" : {
          "USING" : { "list" : [ "users-to-notify" ] },
          "ITEM" : { "current_user_to_notify" : "Current user to notify" },
          "DO" : [
            { "mail" : {
                "to" : [ "current-user-to-notify:mail" ],
                "subject" : "New comment to node with id [comment:node:nid]",
                "message" : "There is a new comment added to the node with id [comment:node:nid]",
                "language" : [ "" ]
              }
            }
          ]
        }
      }
    ]
  }
}