Many shake happened under e-book providers like iOS app store stricter rules about apps that very imposed OwniBooks directly with Apple's, including the introduction of a 30 percent tax on all in-app purchases to compete. While some e-reader applications some changes to the management of Apple charges made, others decided to lock out.
Nook children, has for example no longer provides a link in the app, allows users to buy books from Barnes & noble. The apps Kobo and borders were also modified to cope with the new rules. Meanwhile Amazon Kindle app has removed its "Kindle store button" and instead adds support for magazines and newspapers.
Another big change was the removal of Google Books from the iTunes app store. Google has even a statement about this development to make, but it is possible that the app would be back with Apple's compliance. It must be stressed, however, that users can still purchase iPhone and iPad e-book content outside of the iBook with Safari or any browser.
