Catching Readers Up

It's common in series books for authors to provide some background information about previous books. Some readers like that; some don't. Over on Reddit, a reader commented about John Scalzi's Old Man's War series, asking if perhaps this was done to pad out the length of the book to meet publishers' expectations.

Scalzi, as is his wont, replied at length. Here's a key point:

I do it on the principle that someone who picks up a copy of a book in a series might not know it's part of a series, and/or copies of other books in the series might not be available at the bookstore at the time. So some bit of catching up on events will be useful, and (generally, although apparently not in your case) tolerable enough for the people who have read previous installments.

If you read many series, this is worth a look. 

Personally, I find it annoying if I'm reading the whole series at once, which I sometimes do. In the original publication  of Charlie Stross' Merchant Princes series, there was quite a bit of background padding in the books, because Stross had written them as a trilogy but the publisher split the series up into six books. When they were republished as a trilogy, Stross edited them to remove the bridging material. 

I have wondered if it would be possible to address this, in ebook formats, by allowing readers to hide bridging material, similar to the way that DVDs sometimes have both theatrical and director's cuts of a movie. I know that this is almost trivially easy to do in web-based publications, but I don't know if it would be possible in Kindle or EPUB formats.