The font size on HN is about the same as in a book when the book is held right up against my screen (my screen is almost exactly arm's length). When I hold a book up to my face, at my normal reading distance, the text size is much bigger than HN's and - roughly - the same as the OP.
Do you read childrens' books? :) Well, you are correct, but again it depends on the size of the font on the book, right? Normal book or magazine text seems to be slightly larger than HN test on screen when viewed on "normal" reading distance.
Well, of course, but the book I was referring to was a UK Penguin fiction paperback - pretty much as 'standard' as it gets, although I don't know about international variations.