We have so far only skimmed the article, but quite like the little graphic on the top of page 49 in the print version. "When books are digitized, reading becomes a community activity," it says at one end of a snakey branched line. "Bookmarks can be shared with fellow readers. Marginalia can be broadcast. Bibliographies swapped." And then, "You might get an alert that your friend Carl has annotated a favorite book of yours. A moment later, his links are yours."
Nice. But I always also keep in mind what library thinker Walt Crawford wrote in 1998: "Paper persists." That ever-arriving electronic future still isn't quite here yet.