Lots, but most of the cleverness is behind the scenes, and obviously too subtle for you to notice. Eucalyptus does a really amazing job of formatting the book content so that it’s really close to how a genuine paper book looks. This makes reading it a pleasure. Line spacing, margins, font style and general look-and-feel are, just like on Mac, subtly better than the alternatives in myriad ways – and make a huge difference to the immersive quality of the app.

And how smug is it to say that this will only be of interest to newbies? Don’t sneer at your readers.