It seems like access to data on US soil is a competitive dis-advantage for American companies.
http://www.motherjones.com/mojo/2013/06/fisa-court-nsa-spyin...
This was about Law enforcement, they do need warrants to get and use the data obtained. Data in the US would only need a domestic warrant, which is never going to be hard to obtain. Microsoft was arguing that data in Ireland was out of the domain of US domestic warrents, and the judge agreed.
Your data is safer from the US when it is outside the US. At least law enforcement doesn't have carte blanche access to it.