I've come across it in a couple of Harry Potter fics a long time ago, and I hate with a fiery passion! It's just stupid and shows how little the author knows about writing. If the author's going to put random little comments in amongst their fic, then I don't see any point in reading any more because they obviously have no grasp on how to write something and my time is spent better doing something else - like sticking my head in a toilet!

I have only on occasion put comments in my fic and that was when I knew you and loriel_eris were going to be reading them for betaing, so the comments were aimed at you. And they weren't stupid, either! Also, as soon as the mass public were going to read it, the comments were deleted.

I even dislike footnotes in fic, because it's not the same as in a book where the footnote is at the bottom of the page and easy to see. In a fic, by the time you've got to the footnote, you've completely forgotten what is was referring to and have to scroll halfway up the page to find it!