Portability: Does Apple's iBooks need to go Android?

Carnoy, CNET: "Amazon's app motto is, 'Buy once, read everywhere' and it ran a series of What if you switch?-themed TV ads promoting the concept. Barnes & Noble's app page screams: 'Read what you love. Anywhere you like.' It doesn't have quite as many app choices as Amazon, (B&N is missing Windows iPhone 7 and Amazon has announced a Kindle app for HP's Web OS), but it's pretty close. Kobo, too, has a set of apps for a wide variety of devices. iBooks, however, is relegated to Apple iOS mobile devices (we assume an OS X version is in the works), which is fine for all those people who just own Apple devices, but might seem limiting to those who would consider the possibility of dabbling in other platforms."