Does anybody get the comment about Bill not actually sitting on the notebook? I've re-read the original several times, and it still understand it as Bill sitting on the notebook.
I think that "on top of" is meant metaphorically, as in usages like "the apartment was small so everyone lived right on top of each other". This can be contrived to make a sort of sense if the author (of that anecdote) had been planning to either sneak a peek at the notebook without Gates noticing, or suavely open the notebook "let me check my notes"---which is trickier if you have to say "let me check my notes, if you'll move your elbow, excuse my reach, thanks". Note that the notebook was "on the desk", so sitting actually on top of it would be strange.
But I agree that physically "on top of" the notebook was the first reading I had as well.
I am still confused, even knowing the authors intent it doesn't read at all like Bill sat in front of the book making access difficult/awkward, but rather that Bill literally sat on the book. Especially considering the joke at the start.
It's a footnote, indicated by the superscript "1". The story to which it refers to is linked at the end of the first sentence of the second paragraph. Commentators on HN typically use [1] to indicate their footnotes.
