PS - This was written by nLayer/GTT's CEO, one of CloudFlare's bandwidth providers. They have been a terrific partner and were extremely helpful as we mitigated this attack.
"When the attackers stumbled upon this, probably by accident, it resulted in a lot of bogus traffic being injected into the IXP fabrics in an unusual way, until the IXP operators were able to work with everyone to make certain the IXP IP blocks weren't being globally re-advertised."
It's pretty fascinating and I think most of the HN audience, myself included, would be able to understand the actual technical detail.
I have to smile when people are praising you for the plaintext writeup whose purpose was to link from facebook. It's like saying you finally got your house fully off-grid using your hand made windmill that generates power so you can watch the Kardashians. ;)