Archive Binge -- Mack's first year at MU ends with ch. 496; the second year is up to ch. 85. Also: 117 chapters in Jamie's Tale, 12 chapters of As The Underworld Turns, and 77 chapters of Other Tales (assorted side stories).
Fan Nickname -- "Mack Daddy", for Mack's absent demon father (he's never given a proper name, though in the chapters where he eventually appeared, Mackenzie's mum and the character tags referred to him as "The Man")
Despite Puddy several times approaching Moral Event Horizon moments, and being a generally vile person, she has an extremely loyal fan-following on the forums, even in the face of hostility to and attacks on other fan favorites.
Strangled by the Red String -- A very odd version of it, in that Mack is not going to be allowed to be straight, or celibate, or monogamous by turns. Not only does the story conspire to get her into sexual situations, Amaranth even ordered her to perform a specific sex act with Ian on demand, at any time he wanted, after Mack admitted wanting to do so. Ian balked. He got over it.
Some note that Mack's aversion to ever having children seems to imply that if you have "bad" genes, it's a moral imperative not to have children and pass them on.
Use of the Fantasy Counterpart Culture trope often invokes quite a few [at best] uncomfortable stereotypes, and this series is no exception.
Mack thinks that she has bad blood. She thinks she's evil, remember? Were she to have kids, they would inherit her evil blood. Ergo, her aversion to kids is merely an extension of her own self-loathing, which has in-universe Unfortunate Implications.
The proper reaction to being horribly abused is to fetishize the abuse.