Is the actual content, the material being read, the story itself, on topic?
In other words, if I have an ebook called "The Yellow Submarine" by Some Author, is discussing that story on topic?
No, that would be an off-topic question (and would be better suited for another site, like writers.stackexchange.com).
This proposal is aimed squarely at issues that relate to using the e-book reader's hardware or software. So if, for example, your e-book wasn't being displayed correctly - then yes, the questions would be on-topic.