[nadavwr]

From what little I know, in the US you can only file patents for "method and apparatus". I could be wrong but I think this is a very common restriction in patent systems around the world.

Suppose they file this patent for an ebook reader ("apparatus") with this specific feature implemented in a similar way ("method"). You would be in clear violation of the patent if you were to build and distribute a competing ebook reader with a substantially similar feature. But protection drops off rapidly the further you go from replicating both method and apparatus. I.e. if you only work on a piece of software (absent the ebook reader apparatus) I think you should be fine (but IANAL).

Now suppose you were to publish an Android ebook reader app with this feature, and publish it via Google Play. Supposedly this would result in a combined software and apparatus in violation of the patent. I'm not clear on how this is usually regarded (you'd have to at least worry about patent trolls I assume) but I doubt the patent owner has a legal leg to stand on (which won't necessarily stop them from trying).