[s810]

You're partially right..

http://encyclopediadramatica.com/Denial_of_Service

also, there are irc servers that people set up for different events, but that's getting more into the chanology side of it.

[lpgauth]

aka botnets?

[naturalized]

I do not think they control a botnet- they download that LOIC tool individually, specifically for DDoS purpose. Gawker does not seem to have a serious infrastructure: it looks like they are hosted on DATAGRAM.COM, they do not even have their own IP ranges. So it's probably easy to knock down.