Leaving aside the author's unsubstantial introductory diatribe, he does not properly evaluate the "popover" footnote implementation, which is the clear solution

Leaving aside the author's unsubstantial introductory diatribe, he does not properly evaluate the "popover" footnote implementation, which is the clear solution, nor does he compare it with his three alternatives. Regarding the popover: > We could try to solve that problem by dynamically pulling the content from the footnotes and displaying it in a popover. In some browsers (including yours) that will display like a tooltip, pointing directly back to the footnote marker. Thanks to modern web features, this can be done entirely without JavaScript. > But this is still shit! I see good, smart people, who'd always avoid using "click here" as link text, littering their articles with link texts such as 1, 7, and sometimes even 12. Not only is this as contextless as "click here", it also provides the extra frustration of a tiny-weeny hit target. The claim that footnotes are "contextless" is not sound. One cannot attribute the "contextlessness" of "click here" hyperlinks to footnotes because footnotes and hyperlinks fundamentally differ: footnotes are simply placeholders for additional text and do not call the user to action. Perhaps the author meant that a footnotes's form, i.e. a number or symbol, doesn't provide context for the note itself. While this claim is sound, it is irrelevant because a footnote link shouldn't need context; the sentence provides it. While the claim about a "tiny-weeny hit target" is sound, the author fails to consider alternatives. Increasing font size or wrapping the link in brackets would help the problem. Regarding popovers vs. the three proposed alternatives: i) parentheses; ii) `note`; and iii) `<details>`: 1) All three options are more distracting because they occupy more space. And (ii) and (iii) add color. And I'd guess that readers are more likely to unintentionally skim (ii) or open (iii) because they're primed by other websites. All these modes of distraction run contrary to the purpose of the footnote. In fact, a footnote occupies the minimum space possible. 2) Option (ii) adds lots of unseemly vertical space to the webpage. 3) Option (iii) moves the webpage text below the note up and down. This interferes more with the reading experience than does the static popover. 4) Options (ii) and (iii) are not portable over copy paste. If you copy a webpage with these elements into another file, you'll have to manually rearrange them to appear as actual footnotes. 5) All options, as implemented by the author, eliminate the key-value nature of footnotes. One cannot refer to a particular parenthetical, `note`, or `<details>` because they aren't numbered. While (ii) and (iii) could be numbered with no problem, numbered parentheticals start to look weird. 6) All three options give footnotes more visual presence than they should have. Particularly (ii) will make the footnote seem like the most important quote of the article. Footnotes should be out of eyesight most of the time, just like feet.