Comment It's not Europe's, but the choice of each country. (Score 2, Informative) 206
The matter is more specific than the article leads to believe.
SWIFT is not actually 'moving' it's servers, rather it is adding new servers in Europe. Creating one TransAtlantic zone for messages allowed to reach the US and one Europe zone for messages not allowed to reach the US.
The 'National Member Group Chairperson' of each country has specified in which of these zones their traffic should be traveling in, so with some exceptions each country has their own choice.
Soon every country which has chosen to will keep their inter-Europe traffic within Europe. (exchanges with American banks obviously have to go to America.)
For more information read:
http://www.swift.com/solutions/industry_initiatives/distributed_architecture.page
And:
http://www.swift.com/solutions/industry_initiatives/image_doc/DA_Phase_1_white_paper_200907_1.4.pdf