"With the support of Amazon, we look forward to continuing our growth and providing an ever-improving service for readers globally," said Andrew Crawford, Founder, The Book Depository.
If you don't buy from them then you might not have heard of The Book Depository. They're a UK based online bookseller who sell paper books and offer free shipping to over a hundred countries in the world. That's more countries than Amazon operate in, I believe.
I've been watching TBD for a while now, and it was clear at least 7 months ago that they were outcompeting Amazon. This purchase happened for much the same reason as Woot, Zappos, or any other time Amazon bought out the competition. Basically, Amazon bought The Book Depository because they did the job better in that one niche.
Of course, the other interesting detail here is that the folks at Amazon clearly don't think paper is dead. Otherwise they wouldn't have invested in The Book Depository.
P.S. A little over a month ago I came across a presentation that listed all the different companies and websites owned by Amazon. It's now out of date, of course, but it will still astound you when you see the true size of Amazon's retail empire.