For a "positive" 4chan use, this allowed people to concatenate zip files at the end of jpegs to make "books". It was common to use a picture of a book, and then

For a "positive" 4chan use, this allowed people to concatenate zip files at the end of jpegs to make "books". It was common to use a picture of a book, and then concat the book in a zipped pdf or other text file and then post it.