With movable data centers, Google can easily move them across oceans, as popularity and usage of different Google services inevitably shifts across countries over time, in order to be closer to wherever their users are to reduce network latency.

For example an "Orkut data center" would have been very useful to Google in 2008, when they announced they were moving its operations to Brazil because somewhat unpredictably this is where their core user base developed the most: http://en.wikipedia.org/wiki/Orkut