Slade Wilson (A.K.A. Deathstroke The Terminator) and Brother Blood are significantly different from their comic book counterparts. In the comics, Slade was a high priced bounty hunter in the mold of Boba Fett. In addition, the name Deathstroke was considered too violent-sounding, so the producers decided to stick with his real name. Brother Blood got to keep his codename, but his background was completely altered. He is still a sorcerer, but he was changed to a more traditional criminal mastermind, instead of the demonic cult leader of the comics.
The Teen Titans' real names are: Beast Boy - Garfield Logan; Cyborg - Victor 'Vic' Stone; Raven - just 'Raven' (later she assumes the name 'Rachel Roth'); Starfire - Koriand'r (a.k.a. 'Kory Anders'); Terra - Tara Markov;Robin-Dick Grayson.
In the episode "The Mad Mod", the Mad Mod tries to brainwash Starfire by propping her eyes open and forcing her to watch dizzying images. This is a reference to the Ludovico method used to make Alex non-violent in the movie A Clockwork Orange (1971) which starred Malcolm McDowell, who does the voice of the Mad Mod, as Alex.
The opening credits of the show featured two versions of the theme song: one in English and the other in Japanese. The Japanese version is not a direct translation of the English lyrics. Beast Boy sings a translation of the Japanese Lyrics in Teen Titans: Trouble in Tokyo (2006).
Many parts of the series are inspired by the anime FLCL (2000) , most of them being animation style. Occasionally, these references actually involve story and character points. The most repeated example is Beast Boy's love of mopeds - a Vespa motor scooter (also used here in "Mad Mod") belongs to Haruhara Haruko, the female lead in FLCL
Cartoon Network asked the writer and producers to do something they rarely get asked to do; They were asked to take risks. Sam Register, the Vice President of Cartoon Network, said to the creative team "I want you to do things you're not supposed to do."
When Tara Strong originally auditioned for the show, she thought she'd be a lock for Starfire since she did the voice of Bubbles from The Powerpuff Girls (1998). However, Hynden Walch recorded a really amazing audition for Starfire that just blew the producers away.
The Teen Titan lineup featured in this show is based on the "classic" lineup featured in the 1980s comic by Marv Wolfman and George Perez. Building on the momentum of this series, the comic restored this lineup, teaming them with younger protégés. Missing from that lineup are the original Kid Flash (Wally West, who was added later on) and Wonder Girl (Donna Troy, who could not be used due to the Wonder-Embargo).
The fifth season had a slightly different kind of storytelling approach by having one large arc. This was because the writers thought the Titans grew up a bit after saving the world from Trigon and could handle bigger problems.
DC Comics had originally optioned the Teen Titans to be an animated series in the early 1980s, but since the rights to Robin (in conjunction with Batman) were already held by another animation company at the time, a series never went beyond the development stage.
Near the end of the episode "Revolution", Mad Mod has small statues of Raven, Cyborg, Beast Boy, and Starfire on a chess-like strategy table. The poses are taken directly from the line of maquettes released from DC Direct. A Robin statue was made but wasn't included.
Originally, the creative team wanted to show Terra being part of the group more. More episodes during the second season were supposed to have Terra in them so she would have felt like part of the group. That way, when the betrayal happened, it would have been more of a shock. However, they ended up getting crunched for time and couldn't do that in the series.
The producers were having a really hard time finding the right voice for Raven. Andrea Romano, the voice director, brought Tara Strong in, who originally did her Batgirl voice to read for the part. However, before leaving the audition, she tried a raspy voice which got her the part. The final voice for Raven is a like a raspy Zelda Rubinstein.
Originally, the producers didn't even know they would do a story arc with Slade. They had originally decided Slade would just be behind everything, similar to Dr. Claw from Inspector Gadget (1983), but after looking a few episodes, they decided they were teasing something and if they didn't pay it off, they were going to disappoint a lot of people. All discussions and ideas lead to dead ends until Bruce Timm visited Glen Murakami's office and looked at the scripts for "Masks" and "Apprentice". Timm thought the story was really about Slade trying to take Robin away from his friends.
The Teen Titans were originally animated as part of "The Superman/Aquaman Hour of Adventure" (1967) in three 7-minute cartoons ("The Monster Machine"; "The Space Beast Roundup"; and "Operation Rescue"). The team consisted of Aqualad, Wonder Girl, Kid Flash and Speedy (omitting founding member Robin).
In contrast to the other Tamaraneans shown on the series, all of whom have red hair and green eyes, Blackfire is shown to have black hair and blue-purple eyes. Unlike the comics, Blackfire also has the ability to fly through the air at will.
In the Wolfman/Perez New Teen Titans comics, Garfield Logan was called Changeling. However, the creative team decided to use the character's original codename Beast Boy for the show. The character's codename was changed back to Beast Boy in the comics around the time the show began.
The fifth season at one point was going to be 20 episodes. Slade and the Brotherhood were going to team up at one point and the Chief (the leader of the Doom Patrol) and Robotman were going to appear for another story. Also Thunder and Lightning and Red Star were supposed to make another appearance There was a lot of stuff planned, but there wasn't much time to go forward with those plans.
In the series, there is a character who appears to be the miniature version of Robin and his name is Nosyarg Kcid or Larry. Nosyarg Lcid is backwards for Dick Grayson which happens to be the secret identity of Robin. Also this character shares many similarities with a character from DC Comics called Bat-Mite.
Cyborg's first appearance in an animated TV series was in "The Super Power Teams: Galactic Guardians", shortly before this the 1980s incarnation of the Titans, with a new character called the Protector standing in for Robin appeared in an anti-drug PSA.
The trivia items below may give away important plot points.
The person wearing the Red X suit was never revealed in the series, but there are numerous hints that Jason Todd who became the second Robin (later Red Hood) is secretly Red X. This was alluded to by Beast Boy in the New Teen Titans shorts that aired on DC Nation.
As of November 26 2016, it is now conclusively canon that Control Freak is the one who rebooted "Teen Titans" into the current "Teen Titans Go" incarnation. The episode "TV Knight" of the latter series pointed out its own faults and addressed common criticisms with the new show's non-threatening 2-D potty-humor format in lieu of the original show's deeper format with more meaningful story-arcs and continuous character development.