I'd start with a dictionary. A good dictionary has pictures and historical figures, almost encyclopedic. Then, add video. It's easy to imagine moving pictures in a book. Maybe add sound as well.

Next comes news. The book, somehow, can provide the daily news. It's pretty easy to imaigne daily updates to the book.

Once they see that the book can get the news, it's not to hard to extend the communication to other books. so, you could write in one book, and read the words in another.

I'd say that's about it.