Apple apparently made a wise move adding iBooks as a feature of both iOS 8 and Yosemite. The company said that it has added roughly one million new iBooks users per week since the launch of those operating systems last fall.

The good news was given Thursday by Apple iBooks program director Keith Moerer at the Digital Book World conference in New York City.

The announcement, which happens in the shadow of Amazon’s commanding presence in e-books, suggests that Apple is serious about making a play for leadership in the space. Just the fact that Moerer spoke publicly at the conference suggests Apple is intent on making that point.

Moerer said that the larger screen sizes of the new iPhone 6 and iPhone 6 Plus are probably accounting for the increased iBooks uptake. He says a greater proportion of new iBooks users are coming from phones, as opposed to tablets or desktops.