Yup – today (14.11.2010) the 4Chan DDoS attack was to begin against tumblr. Instead 4chan is down. Of course tumblr users plan counterattack for 15.11.2010 (monday), but is there a possibility that the reason for 4chan to be down is that the tumblr attack was moved up in time. For now all 4chan service is down and some sites in tumblr as well.
The flyers are pretty cool: