Originally Posted by JSWolf
For B&N ePub with DRM, when you remove the DRM, you have a standard ePub.
iBooks eBooks may or may not be standard ePub under the hood once the DRM is removed. Same maybe goes for iBooks eBooks without DRM.
And if you strip Kindle DRM and convert it to ePub, that is also standard ePub.
But other then B&N & Apple, all other reflowable ePub (with Adobe Adept DRM) is standard ePub. Outside the USA, there is no B&N and Apple selling their flavors of things
That simply isn't true.
The iBookstore is not US-only.