Snow Crash/WMG

Uncle Enzo is Y.T.'s father

 * Really, it makes sense:
 * When the two first meet, Enzo seems a lot friendlier than you'd think he'd be to someone who merely delivered a pizza.
 * Towards the end, he's got a new skateboard that he says he wants to give Y.T.
 * Surely he's just very grateful because she saved CosaNostra, and hence Uncle Enzo, alot of trouble and face by delivering Hiro's pizza at the start of the book? This being the mafia and all one would hope they'd want to keep up their image of rewarding loyalty and good service. And why would someone like Enzo have romantic relations with a drudgeon working for the Feds?
 * If Uncle Enzo is her father, then wouldn't he have seemed a bit familiar to her? Y.T. is not a character who never knew her dad; late in the book, she recalls how her dad left her and Mom. If she ran into her dad again, she'd probably recognize him.
 * Grateful is one thing, and I can write off the skateboard for that. But he seemed genuinely excited about it, as a gift. Moreover, he gave her his dog tags. That's not the kind of thing you just give someone who did you a relatively minor favor (yes, pizza delivery is serious business, but that seems to be a Disproportionate Reward).
 * I also got the strong impression that Uncle Enzo's behavior implied he was YT's father, including the comments he made about YT's mom that sounded vary familiar. As for the mention of YT's dad walking out, I'd always assumed that Enzo was YT's biological father, either from an affair or from before YT's mom got married. It's easy to see the two of them breaking up because "I'm in the Government, you're in the Mafia, we can't be together."
 * Given the characters' respective ages, it's also possible he might be her grandfather. We know nothing about her parents' backgrounds, and her Mom might've had to cut all ties with her Mafia relatives or in-laws in order to work for the Feds.

"Never Gonna Give You Up" is the English translation of the nam-shub of Enki

 * If for no other reason than for . "You know the rules, and so do I!"

Y.T. is Miss Matheson, in The Diamond Age.
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.

Uncle Enzo was training Y.T to be his replacement.

 * He constantly thinks and talks about how much he dislikes the younger members of the Mafia, and how they lack imagination, and spunk, two things that Uncle Enzo sees a massive amount of in Y.T.

Raven never had a Dead-Man Switch on his bomb.
He was playing the Soviet side in a cold war of his own; implying (or in this case outright stating) that he had a Mutually Assured Destruction system in place (heh, I only just noticed the acronym), without actually having one. He could have been wired up by one of Rife's techno-savvy Orthos, but it seems slightly unlikely. The most important part, to me, is that if he had had enough metal in him to send a message to the bomb when he died, he would have had enough metal to be seen on the radar near the end, since it was stated to be looking for metal in general and not just weapons.