The parent is referring to people selling their bitcoins, then launching a DDOS attack on the exchange server to get the rest of the world to sell in panic, and

The parent is referring to people selling their bitcoins, then launching a DDOS attack on the exchange server to get the rest of the world to sell in panic, and then buying back bitcoins at the lower rate. I haven't been following the bitcoin news carefully, but presumably that's been going on recently.