Giles mocks his book's description of the Bringers with the following line: "They're rebels and they'll never, ever be any good." This is a reference to the song "He's a Rebel" by the 60's band, The Crystals.
They eyeless "Bringers" in black robes, which return in Season 7, are a nod to The Devil's Rain (1975) which features acolytes of a satanic cult in the same look.
Reveals the real reason Angel was brought back from the Hell universe.
Sarah Michelle Gellar's hairstyle changes a couple of times in different scenes. From shorter, unflattering, and straight with bangs to her usual longer, full and wavy style.
The snow was artificial, as southern California was going through an extreme heat-wave at the time. The ground would have been too warm to accumulate that much precipitation so quickly, let alone at all.