Actor Allusion: When Femme Fatale challenges the Powerpuff Girls to name some memorable female superheroes, Bubbles mentions Supergirl and Batgirl. Bubbles's voice actor, Tara Strong, voiced Batgirl in The New Batman Adventures some time earlier.
And You Thought It Would Fail: The test screening for the first pilot was an absolute disaster, with children complaining about the unusual character designs and one even going as far as to say that Craig McCracken should be firednote This kid would later serve as the inspiration for the show's bully Mitch Mitchelson. Craig went to work redesigning the characters with more traditional features, but then-president of Cartoon Network Mike Lazo reassured him that a negative reaction was better than a lukewarm reaction, and that they shouldn't change a thing.
Banned Episode: The season 5 "See Me, Feel Me, Gnomey" was banned in the US, due to the heavy use of strobe effects (which would have triggered epileptic seizures in more sensitive viewers, much like the notorious Pokémon episode "Electric Soldier Porygon." Reportedly, it was banned for allegedly having Communist undertones, but this was never proven). The episode can now be seen on the complete series DVD set for the show and on the complete series collection on Netflix. It aired in Canada on March 18, 2004.
Box Office Bomb: Warner Bros' marketing for the movie was quite lousy (as stated in the main page), but CN did their part and promoted it to heck and back (even [adult swim] got involved). Outside the channel, however, there was barely any mention of it. Not helping was it was pitted against Men in Black II on the opening weekend, was overshadowed by the surprise hit Like Mike and Warner Bros focusing their campaign on the Scooby-Doo live-action movie. As such it preformed poorly. Because of this, the series finales for Ed, Edd 'n' Eddy and Codename: Kids Next Door were scaled back to made-for-TV fare rather than made into feature films.
Creator Backlash: While she stands behind the message of the episode to this day, Lauren Faust has regretted Equal Fights because she wrote it out of Old Shame for her own phase as a hateful misandrist and feels that the subject matter was too complicated for children to understand.
Development Gag: The designs of the Run-of-the-Mill Girls from "Oops, I Did It Again" were based on redesigns Craig McCracken came up with after the early pilot received negative test audience reactions due to the girls' bug-like designs.
Executive Meddling: According to the producers of the 2016 reboot, Sara Bellum was Put on a Bus because she was "inappropriate". Considering Miss Keane's breasts were removed (!), it's kind of obvious what the producers have an issue with (presumably they're the same guys who have been making Regular Show be edited to remove some objectionable content recently).
In Memoriam: The episode The City of Frownsville was dedicated to those who were killed during the events of 9/11, which happened just before the episode aired.
Keep Circulating the Tapes: "See Me, Feel Me, Gnomey" has never been shown in the U.S., not even in the current runs on Boomerang. It is on the complete series DVD set and on Netflix, though.
Cristina Hernandez (Blossom) and Rossy Aguirre (Buttercup) voiced Lime and Cherry respectively, two girls from another trio of super-powered girls living with a guy, except their personalities are different between the two series.
Also, Cristina Hernandez, along with Enrique Cervantes (Mojo Jojo) and Sergio Gutierrez Coto (The Narrator) voiced Catwoman, Bane and Batman respectively. That's right, The Narrator is the The Dark Knight and he's fighting against Blossom and Mojo Jojo!
Fingerless Hands: Former Trope Namer (the trope used to be called Powerpuff Girl Hands). One of the most notable aspects of the Powerpuff Girls' character designs is that their hands lack fingers and thumbs.
So Once Again, the Day Is Saved: Nearly every episode ends with the Narrator saying "So once again, the day is saved thanks to the Powerpuff Girls", with occasional variations.
Before the Girls, Craig played around with a luchador superhero character as the star for his thesis film, but after drawing a birthday card for his brother with three cute, Margret Keane-inspired girls, he though the idea of those little girls fighting bad guys was hilarious and chose that instead.
The original tone of the cartoon was meant to be much more adult (it was called "The Whoopass Girls" after all). One can only imagine what that series would've been like if Craig hadn't made it more kid-friendly.
One planned episode, Deja View, about the girls visiting an alternate universe ruled by their evil versions, ended up being cancelled due to the visuals requiring the budget to go overboard (which they were already stretching). It wound up being given to the comic book writers and turned into the 50th issue.
As said on the main page, Craig wanted Jack Black to voice the Gnome in "See Me, Feel Me, Gnomey", but they couldn't due to him being too busy and expensive.