Words in stone and on the wind

After I wrote, in a recent Wall Street Journal article, about the malleability of text in electronic books, a reader asked me to flesh out my thoughts about the different ways that "typographical fixity" - to again borrow Elizabeth Eisenstein's term - can manifest itself in a book. I've been thinking about that and have come up with four categories of fixity or stability - not all of which are typographical in nature - that influence the permanence of a book (or other written work) and that change, sometimes radically, as we shift from print publishing to electronic publishing. I'm sure this isn't a complete list, but I hope it's a useful start: Integrity of the page. At the simplest and most fundamental level, typographical fixity means that when you have a page printed in ink, you're able to trust that the page will maintain its integrity; when you pick it up tomorrow, or twenty years from now, its contents will be the same as what you see today. The printing press didn't create this type of fixity - it was there with the scribal book, the scroll, and certainly the stone tablet - but it did extend it into...