Not bad kerning either, necessarily. (It's automatically kerned by the type engine regardless of the letter-spacing property.) Just loose tracking. It's fairly common for typographers to track bold text slightly looser than book text so as to lighten its typographic color.
Since I was about to say the same thing you already did, I’ll add that the difference is that kerning refers to adjusting the spacing between specific character pairs instead of the whole text (which is what letter-spacing/tracking does). For example the AV pair usually needs to be kerned to make the glyphs partially overlap so that they don’t look too far apart.
The interesting thing is that "view selection source" on instances of the 'kerning' word don't show any shenanigans. Gotta dig deeper... Edit: ok, it's "em{letter-spacing:1px}" in the CSS.
I had no idea… thanks for pointing that out. Doesn't seem too useful for those of us that can see the comic for ourselves, but a nice easter egg nonetheless.
