Roland Barthes used his card index as more than the traditional bibliographical, excerpting, and note taking tool that many had before him. He also used it to accumulate notes on what he had seen and heard in his daily life, phrases he liked, and plans. It came to serve the function, particularly in the last two years of his life, of a diary or what biographer Tiphaine Samoyault came to call his fichierjournal or index-card diary.

Are there examples of this practice before this time? Certainly in the commonplace book tradition, the ideas of journal, diary, and commonplace had been mixed before.