The Diamond Age takes place in the same universe as Snow Crash, perhaps a century or so later. Miss Matheson is unusually old, well over 100 (Nell estimates her to be between 800 and 900, but that's neither here nor there). She used to be a skateboarder, and remembers an add about "Chiseled Spam" from her younger years. She had a friend who tried to teach her the martial arts (probably Hiro Protagonist). Sadly, this means that poor Y.T. became paralyzed "early in her career." But, at least she still grew up to be a cool old mentor for Nell.