1) They forgot to the pay the monthly bill to the hosting company. lol
2) The hosting company may have taken the site down due to its nature.
3) Its a hoax and the Account Suspended page is a fake perhaps?
4) Maybe it wasn't Annonymous behind that website?
5) Doing a quick google about Annonymous attacking/hacking virgin brings up this thread at TK, so maybe the entire site was a hoax.