I use the category note field as a reminder for the "article template" I use for the articles in that category.
An example of a category note: always add module 20 (using module anywhere) at the bottom of the article.
To save me time I would like to display this note when I am on the article manager page so that I can see it just before I click on "create a new article".
EDIT: Another way of doing it, could be to have sticky notes on backend, or an extra field in the article editing page so that I can see this reminder. Note that simply adding another field to the article as describe here won't work as I don't want to add new info on each article but rather the opposite: the same reminder should be display on all articles.