The book, which sells for $24.99, was initially offered as an iPhone app for $4.99.
Instagram was only launched in October 2010 - initially just for the iPhone before being offered as an Android app last week.
Digg Reader is bundled into the Digg iOS app instead of being offered as a standalone app because the company sees Digg.com and Digg Reader as complementary products.
Monument Valley's expansion is coming to Android "soon after" its launch on iOS, according to Ustwo, and will be offered as an in-app purchase for just $1.99, providing eight brand new levels for players to explore.
He suggested "Chimes of Freedom" should have been offered as a phone app with "all the music, behind-the-scenes videos, information about Amnesty and updates about political issues".
To be clear, Digg Reader will not be offered as a separate app, but will be bundled into the company's main Digg.com mobile application on both platforms.
Not every service should be offered as a native app, and the same is true for chatbots.
While LocalVox isn't sharing the financial terms of the deal, it has acquired Postling's technology and platform with the acquisition, however, the startup's Social Inbox will continue to be offered as a standalone app on Postling.com.
DOMO is being offered as a "pre-social" app, which makes use of your interest graph and location to make it easier to connect with people who are similar to you and physically near you ("pre-social", because these people are initially strangers).
Even in rival mobile interfaces, you expect to find apps offered as an array of icons; to have notifications about events in a sliding layer at the top; and get easy access to key functions such as Wi-Fi and Bluetooth from any screen.
