Publisher's Weekly are reporting:
Ever since Amazon released the news Monday that it was now selling more e-books than hardcovers, the industry has been examining the veracity of the claim. Amazon, after all, has a tradition of releasing selected figures while withholding total sales numbers, just as it did in this case by not releasing actual sales for e-books, hardcovers or Kindles. Some suggested that Amazon’s e-book to hardcover sales ratio was only for customers who shop in the Kindle store, not for all customers. But Amazon was adamant the figures included all customers of its U.S. book business, and the e-tailer’s claim has been supported by publishers.
I don't know what amazes me more, that PW actually reported this as news, or that so many people repeated it. No, seriously. This barely qualifies as a tweet. What, did you really think Amazon were going to lie?
Note that I'm not criticizing PW for double checking the facts. But this would only be news if the publishers had disagreed with Amazon.