4chan hacked a hip hip board/website last summer. The board was down for about 3 months while they did upgrades. The main page itself was down a week or so, but was totally overhauled and barebones for months. It was brutal, but brought on by a handful of ignorant posters who went over to 4chan.org and set them off on purpose while the admins/mods of the message board sat and did nothing to shut those few posters up.
I think *generally* if you don't mess with them, they don't mess with you.