This set up a crossover with Angel episode In the Dark (1999), broadcast the same evening, in which Oz guest stars. Spike and Oz are the only characters to appear in both episodes.
Joss Whedon has said losing Cordelia as the voice of reason, who wouldn't sugarcoat things for the Scooby gang, changed the dynamic of the show and he realized they would need someone to fill her absence. This opened the door to bringing Spike on as a cast member for the rest of the series. He would appear in every episode starting with episode 6, Wild at Heart.
Buffy explains she was bitten by an "angry puppy"; Willow's vampire double also referred to Angel as "the puppy" in The Wish (1998).
The artist performing at the party is Bif Naked. Some of her songs are also featured throughout the episode.
When Buffy is on the phone with Giles telling him about the Gem of Amara, on the side of the payphone "Cordy sucks" is part of the graffiti. This could be in reference to Cordelia, who left the show after season 3 to star in Angel (1999).