AlexMuir has missed the most important point: Megaupload served infringing content from machines based in Virginia, overseen by the hosting provider Carpathia. The fact that the persons involved were not US citizens or that the company was based in Hong Kong are irrelevant. The servers (some of them) were in the US, not far from a court where a warrant could be obtained for anyone with cause (e.g. the FBI, DOJ) to look at all ingress and egress from those servers.

Game over.