Attacker couldn't afford to DDOS the blockchain - which will only happen very quickly btw since consumption will be too big and the speed it so fast!
What a robust blockchain right there! :D With busy.org and other Steem block explorers standing up during the attack, it only proves how Steem blockchain is not feasible for attacks with its transparency, speed, and rate-limiting. Kudos to steemit team and graphene!