I have a lot of technical ebooks and I often have to rummage through each one to figure out where I saw something previously. Is there some tag within your e-books such that I can combine all of the index entries into one large index at the back of my ebook reader? Something that would have the index entry and then the title and page number? It would make my life so much easier. Even without page numbers it would seem that with semantic marks you could at least index and jump to the location.
It's a great idea, and something we've thought a lot about. We're working on a full book content search, as opposed to just the index, that would provide complete access to the books you own and previews to those that you don't. This is on our project roadmap, though I don't have a launch date at this time.