Yes, if they have operations in the US they can be prosecuted, I believe. What's even worse for Megaupload in this case is that they had started legal proceedings themselves in the US. If they can use the US law, they have to abide them.
If every website suddenly has to obey the laws of every country, it will be an interesting time.
If every website suddenly has to obey the laws of every country
The DMCA was the US implementation of two international treaties.
I'm sure those kidnapped will be glad to hear this.
Not really a new or particularly controversial legal construct. The host country can refuse to extradite if they disagree with the charges.