Actor Allusion: Sora hilariously Lampshades herself in a No Fourth Wall session in one of the drama CDs, where she complains about sounding like an "old lady." Though 34 (the age of Yuko Mizutani when she voiced Sora) doesn't seem to be that old, it certainly qualifies as Dawson Casting! In addition to this, another drama track consists of a radio show recording DJ'd by Sora, which alludes to how Yuko Mizutani ran a radio show years back.
Adored by the Network: While it didn't save the block, Fox Kids touted this show like crazy come time to air the dub, especially in the midst of the Pokemon craze that allowed Kids' WB! to be the dominate Saturday Morning block at the time. The fact the show managed to win over a large part of that crowd allowed Fox Kids to stay afloat a bit longer.
Celebrity Voice Actor: Lara Jill Miller was better known for her role as Samantha "Sam" Kanisky in the 1980's NBC sitcom Gimme a Break!. People magazine wrote an article on her when she returned to Hollywood in 1999, just as Miller was voicing Kari for Digimon.
God Never Said That: Like most character names in the English dub, "Hikari" was shortened to "Kari." Unlike the others, however, no official material released in English has ever referred to her name in full as "Hikari 'Kari' Kamiya."
Word of Dante: She is called "Hikari Kamiya" by Wizardmon in the English version of the highly compressed Digimon manhua. Which was produced by Tokyopop, of all things, not Saban or Disney's Sensation Animation.
The Other Darrin: Taichi is given a different voice actor (Jason Spisak) for the dubbed version of the fourth movie, Revenge of Diaboromon, because Joshua Seth (his original voice actor) had already retired from the entertainment business by that time.
The PSP adaptation also has Devimon played by Ryotaro Okiayu, as Kaneto Shiozawa, who voiced the character in the original anime, died in 2000. This is amusing (or disconcerting) when one takes into account that Ai Maeda, who voices Mimi, married Ryotaro Okiayu shortly before the game was released in Japan.
Real Life Writes the Plot: When the crew went to visit Odaiba in order to see a reference for the real world scenes, the place ended up covered in fog. As a result, they decided to cover Odaiba in fog, creating a major part of the Vamdemon (Myotismon) arc.
Relationship Voice Actor: If you're an unrepentant fangirl, this allows for a probably-unintentional-yet-still-amusing, very brief moment, when Matt's dad helps carry Wizardmon around. Ishida and Hirata's characters in Saiyuki do that for each other quite a lot...
In the Mexican Spanish dub, both Hikari and Gatomon shares the same voice actress (Cristina Hernandez) and they literally talking to themselves.
Joe, his two older brothers, and his CD drama-only parents are all voiced by Masami Kikuchi. Including his mother. Indeed, a Crowning Moment of Awesome for Mr. Kikuchi—one interview with him and Koushirou's VA, Umi Tenjin, talks about how surprised the other actors were when he switched between all of the characters in real time.
Tentomon, for a brief moment in the dub, when Izzy's parents find out about him.
Agumon and Shellmon are both voiced by Tom Fahn in the English dub.
Mostly avoided with DemiDevimon, but he does interact with Digitamamon, another of the Digimon that Derek Stephen Prince voiced in the dub.
Technology Marches On: The movie made a plot point out of Infermon taking over the phone system, forcing Izzy to get a wireless satellite uplink. This doesn't mean as much now that wired connections and phone modems have become obsolete.
Toy Ship: Really any potential ship is this since the kids range from 2nd grade to 6th grade (though the English dub seems to have aged up the older kids to middle school) but TK and Kari are the most egregious example being only 8 years old.
What Could Have Been: According to this interview with the series' co-creator, the infamous 02 epilogue, in which Sora and Yamato ended up married was originally planned for this series.
Word of God states that Kari originally wasn't supposed to be a DigiDestined, and was only supposed to be a Mysterious Waif side character. Come the middle of the series, when the staff wanted to add a new character to the seven, they decided to expand Kari's character by tossing her onto the team. This kind of explains her Canon Sue tendencies, if you think about it.
For some reason in the dub Gatomon was initially made male inversing She's a Man in Japan, three episodes were even recorded with Gatomon as a boy luckily the dubbers realized their mistake before it was too late and rectified it before any episodes with male Gatomon aired and the unfortunate problem of a boy Gatomon turning into the very female Angewomon. Though this begs the question if that meant they didn't get to see the original episode to see that Gatomon was female or They Just Didn't Care