At any point in time, the available technology -especially transportation and communications technologies - largely determines which goods and services are easy to trade internationally and which are hard or impossible to trade.

Because technology is constantly improving, and because transportation seems to grow easier and cheaper over time, the boundary between what is tradable and what is not tradable is constantly shifting--just as patterns of comparative advantage are. But this shift is not kaleidoscopic. Rather, it moves inexorably in only one direction: Over time, more and more items become tradable. In particular, boxes aren’t what they used to be. The old assumption that, if you can’t put it in a box, you can’t trade it, is now hopelessly obsolete. And that is the second critical point in understanding the phenomenon of offshoring. Because packets of digitized information can now play the role that boxes used to play, many services are now tradable and many more will surely become so.