We are still actively working on the spam issue.
Distributed in a variety of formats such as .pdf and .mobi, books are wads of text intended for educational or entertainment purposes.
Audiobooks (sometimes called Talking Books) are audio files in which a well spoken person reads the book to you, similar to a podcast.
Once upon a time books were distributed physically using dead trees (similar to toilet paper). This is rare now.
Magazines were similar to books, but lighter. They often comprised of many short articles which spanned only a page or two out of a 50-100 page magazine. They were distributed weekly or monthly and would often include sections such as "news" and "letters to the editor". It was possible to "subscribe" to a magazine, where a subscriber would pay for a year's worth of magazines in advance and have them home delivered.
Magazines were replaced by websites and comment sections on the web. They have died a very slow death, relying on technological illiterates to continue buying them.
Some magazines still exist in an online-only format, but tend to update daily rather than weekly/monthy and are "magazines" in name only.