Douglas' point that these atrocities have largely been forgotten outside the affected areas, though, is well taken. And, as he highlights, the involvement of the Allies' governments outside of the Soviets, has not been fully revealed. The article proves to be an introduction to Douglas' upcoming book Orderly and Humane: The Expulsion of the Germans after the Second World War. (A search on his book title should turn up other books that address this topic, too.) From the book description:
Immediately after the Second World War, the victorious Allies authorized and helped to carry out the forced relocation of German speakers from their homes across central and southern Europe to Germany. The numbers were almost unimaginable—between 12,000,000 and 14,000,000 civilians, most of them women and children—and the losses horrifying—at least 500,000 people, and perhaps many more, died while detained in former concentration camps, while locked in trains en route, or after arriving in Germany exhausted, malnourished, and homeless. This book is the first in any language to tell the full story of this immense man-made catastrophe.
Based mainly on archival records of the countries that carried out the forced migrations and of the international humanitarian organizations that tried but failed to prevent the disastrous results, Orderly and Humane: The Expulsion of the Germans after the Second World War is an authoritative and objective account. It examines an aspect of European history that few have wished to confront, exploring how the expulsions were conceived, planned, and executed and how their legacy reverberates throughout central Europe today. The book is an important study of the largest recorded episode of what we now call "ethnic cleansing," and it may also be the most significant untold story of the Second World War.
As Snyder aptly put it in his book, there is an ongoing "competition for memory" and Douglas' book looks to be another history looking to point out the shared aspects of separate narratives.
Update (11 Aug 2012): Andrew Stuttaford's review in The Wall Street Journal