So I noticed.
DDoS = Distributed Denial of Service
aka 'hacked'
Hacked is not a term that typically describes the receiver of a DDoS; they, as in the upstream ISP in LiveATC's case, are just a victim. The ISP's server is on the receiving end of an uninterrupted and coordinated storm of packets sent by thousands of zombie computers, which are most likely Windows computers compromised by a Trojan and owned by naive computer users across the world. Any web-facing server, i.e any website or intermediary server that sends traffic to websites, can be victims of a DDoS attack.
There was a fascinating personal tale written by a well-respected security guru, Steve Gibson of a DDoS attack against his site. It read like an exciting drama. I was going to post the link but I could not find it on his site. This occurred back in 2000 or so, but the story was such a classic that I expected it to live forever on GRC.com. Oh, well - if someone runs across it please post the link here.