Channel Hop: Started out on Nickelodeon. Then moved to ABC. Then finally to the Disney Channel before disappearing off the radar completely.
It's all very complicated company politics. Jumbo Pictures first managed to sell some of their ideas to Viacom and become a partner, subsequently getting on Viacom's payroll. Shortly after the wrapping up of Season 4, Viacom shafted them. Conveniently, right after Viacom gave them the boot, Disney came up to them and sweet-talked them. They cut off all ties with Viacom and then managed to partner up with Disney instead, getting on Disney's payroll. Which after 4 seasons and a movie, ended in another dispute because Disney used Doug and PB&J Otter characters in a multi-network music video project that Jim Jenkins did not want the characters to be participating in due to his own beliefs. They then broke up their ties with Disney, changed the company name to Cartoon Pizza, and learned the hard way the downsides of partnering up with a major television network.
Creator Backlash: Jim Jinkins wasn't as involved with Disney's Doug as much as people often thought he was according to Mathew Klickstein's book Slimed: An Oral History of Nickelodeon's Golden Age. He's one of the few creators that actually agrees with the majority of the fanbase that the Nickelodeon version was better except for "The Dark Quail Saga". Constance Shulman and Billy West prefer the Nickelodeon version too.
Cross-Dressing Voices: Averted in the American version, all of the male characters are done by males (save for Elmo, he's done by the same girl as Beebe), though Doug is done by female voice actor Masako Nozawa in Japan.
Not quite averted: Doug's grandmother was voiced by Fred Newman, who also played Skeeter, Mr. Dink, and others.
God Never Said That: Since Doug started in the 1990s, it was often rumored that Skeeter was suppossed to be the Black Best Friend (but depicted as blue, as blue and purple are often used in sci-fi and speculative fiction to depict black people or any minority who isn't white). Jim Jinkins has stated that he didn't color Skeeter blue as a substitute for making him black; he made Skeeter blue because he thought he looked good that way.
Latin America: Patti Mayonnaise was voiced by Sailor Moon, later by Sailor Mercury.
Keep Circulating the Tapes: While the Nick series has DVDs on Amazon, there's the good chance of playback errors, and two episodes are missing from season four because of "technical difficulties". However, there are torrents available of all four seasons of the Nick series. Played completely straight with the Disney series, with the videos out of print and only a handful of episodes online. Heck, The Movie hasn't even been released on DVD (though it is available for video rental/purchase on Amazon).
iTunes has all four seasons, and the two episodes missing from the Season 4 DVD have been reinstated.
The movie was released on VideoCD in many second world countries. The catch? Was. It's out of print.
And well, iTunes does not sell TV series to many parts of the world, and the Disney Movie Club is very likely US-only...
The Other Darrin: Thomas McHugh and Chris Phillips replaced Billy West (who didn't want to be part of the Disney variation of Doug) as Doug and Roger's voices, respectively, in the Disney series. This was made note of with Doug in its first episode.
After Billy West left, Roger ended up talking to himself with Boomer's voice actor in the Disney series.
Judy shares her voice actress with her mom Theda.
Whenever two of Fred Newman's characters (Skeeter and Mr. Dink, for example) talk to each other.
What Could Have Been: The original Doug product was going to be a children's book, Doug Gets a New Pair of Shoes, until the creator found out that Nickelodeon was looking for cartoonists for new original cartoons (during this time, all of Nickelodeon's cartoons were either imported from other countries [mostly from continental Europe, Japan, or Canada] or part of a syndication package [the Looney Tunes shorts and the UPA cartoons of the 1950s]), and decided to turn it into a cartoon series. The book ended up serving as the episode Doug's Cool Shoes in season one.
Roger was also going to be a rival to Doug for Doug's love interest, Patti. This was scrapped, and the role was taken by Guy once the show was switched over to Disney.
The movie was also going to be a Direct-to-Video release, but Disney decided put it into theaters due to the success of The Rugrats Movie. Critically, it didn't work. In box office numbers, it grossed much less than Rugrats, but it was still a huge profit for Disney.
The movie was also going to be made by 20th Century Fox in 1993, along with movies for Rugrats and The Ren & Stimpy Show. Nick's contract fell through before they could make a movie deal. So once Viacom (Nick's company) bought Paramount, Rugrats got its movie, Disney ended up making Doug's movie, and Ren and Stimpy never got a movie. It's unknown whether Fox's version of Doug's 1st Movie would've been the same movie as it became.
Also, the movie was originally going to be called The First Doug Movie Ever, but was later retitled to Doug's 1st Movie.
Much like Rugrats, Doug's popularity and ratings really soared when it went into daytime syndication. But Disney bought the rights to the show and sweet-talked Jumbo Pictures into dumping Nickelodeon (note: Jumbo and Nick are already on sour terms at that point) before Nickelodeon had a chance to uncancel it.