In the short term, publishers and retailers may promote their wares direct to readers through media like cable television, the postal service, and online services, and later, the reader's portable or home computer. But the need to announce new books could eventually fade if readers can do their own searching for books that they may be interested in. Eventually their portable or home computer could do the searching for them--continuously, perhaps storing a backlog of books to be considered.
Electronic books are inherently more plastic than paper books. A decade hence many distribution schemes may coexist: normal paper publishers, locked or unlocked single-title disc publishers, on-demand disc or paper publishers, prerecorded full-list locked-disc publishers, and subscription publishers.