This is the first episode to feature the title of the episode onscreen.
The plot is heavily reminiscent of Neil Gaiman's novel "American Gods". Show creator Eric Kripke has cited Neil Gaiman and "American Gods" as influences for the show.
The college professor that Dean meets with is William B. Davis, better known as the Smoking Man, from the show The X-Files (1993). Supernatural is said to take some inspiration from this show and has several nods to it throughout the season.
The supposed apple orchard has trees with no central trunk but several limbs coming straight out of the ground. Apple trees are never pruned to that shape, but hazelnuts routinely are. Hazelnuts are a major crop in Oregon and British Columbia (where Supernatural is filmed).
One of the contacts in Dean's phone is "Carmelita" a character from the fake porn series "Casa Erotica" frequently featured in throughout the series.