[onetwothreefour]

They're not expanding to Ireland. That's the point. Now they route all transactions from non-US customers through the Irish subsidiary and keep their money over there. They pay up 15% or whatever the tax rate is instead of the 35% over here. They keep the profits there waiting for a tax holiday, then move the money back when that happens. They can probably even claim the 15% as a foreign tax credit during the tax holiday.

Pretty simple. :)

While not illegal, it's a little bit dodgy. But it's what everyone does these days, so why not?