I have always been a fan of footnotes. No, not the dry, academic, here-is-the-obscure-journal-where-I-got-this-from kind, but the David Foster Wallace let’s-go-on-a-tangent variety. Bill Simmons is from the latter school as well, and footnotes figure predominantly in the articles on his site, Grantland</a>.

From what I can tell poking around, javascript is used to measure the vertical position of the footnote in the text and the footnote itself is relatively positioned the same amount from the top. Nicely done.