BlackSpace is a document reader that can only be described as the next level as theres certainly nothing like it currently on the Market and the good news is that its now available for MeeGo.
... the xBook reader is more then just a reader as it allow for an unlimited number of rich multimedia layers to be added to eBook. In addition to adding video to your book you’ve got the ability to converge audio, photo, texts and websites directly on the document as well as in annotations that are represented by pins. Since this is a product targeted at students the ability to cut and past portions of the document is available and it is also position to move the information between ebooks.
It is available / coming soon on Android, iOS and Linux and Windows has a book viewer. Unfortunately they are channelling this product directly to OEMs and ODMs.