Buffy tells the Potentials that her death could make one of them the next Slayer. Dawn also makes the same assumption, stating that if she were to become the Slayer, it would mean that Buffy had died. It's known that Faith became a Slayer after Kendra died, but the possibility of the line continuing due to another death of Buffy is never clear in the series, even after her death, when no new Slayer is discovered or mentioned.
The role of Amanda, who first appeared in Help (2002), was originally intended as a one-time part, but was brought back as a recurring character due to Sarah Hagan's connection to writer Rebecca Kirshner, who wrote for Hagan's previous series Freaks and Geeks (1999).
The twelfth episode of the season was generally the episode in which Buffy has her birthday. Apart from the first season, which was a mid-season replacement and probably began just after Buffy's sixteenth birthday, this is the only season where Buffy's birthday isn't acknowledged. In the birthday episode of the previous season, Older and Far Away (2002), Spike did suggest Buffy should not celebrate her birthday anymore.
Andrew makes references to Dragon Ball Z (1996), Vegeta and Goku when trying to express his desired role in the group, and also asks Dawn if she wants to "play Dragon Ball Z". James Marsters, who plays Spike, portrayed Piccolo in Dragonball Evolution (2009) and is an open fan of the anime. He would later voice Zamasu in the English Dub of Dragon Ball Super (2015).
Dawn says to Xander, "You had that sexy army training for a while," which refers to Halloween (1997). Although Dawn didn't appear in this episode, as reality was not yet modified by monks of the Order of Dagon, Dawn is present in their memories and they in hers. She also smiles fondly at the mention of Oz although the two characters never meet onscreen.