The U.S. government has declared that hacking can now to be considered an act of war in certain circumstances. Until now when someone hacked into a system they could eventually be traced and get some fine or even prison time and such. Now if it's an act of war, well, I guess they consider they can now just bomb your place or something. I'm not sure how this really works.
Lulz Security, or LulzSec, is a serious organisation that doesn't like to laugh. So they hacked into some FBI affiliated website, infragardatlanta.org