To help me put this together, please post your questions here, either questions that have never been answered before, or frequently asked questions which you think should be listed in the FAQ. Thanks.
EDIT: I'm putting the list on the first page and pinning this thread for easier perusal.
Q: Is it true that there won’t be a third season?
A: In all likelihood the show will indeed end with the 52nd episode as there is very little to no interest both from the investors’ and the producer’s side in making a third season of W.I.T.C.H.
Q: Why do the US and the European opening credits differ?
A: Because the US picked a different theme song, they preferred to adapt the images to the music as opposed to the other way around, and so they cut their own version of the opening credits.
Q: How come some of the scenes shown in the US opening credits were never seen in any episode of the series?
A: Because these scenes are demo reels from the various animation studios that SIP Animation tested for the first season.
Q: Why did the US edit out two scenes from the episode “It Begins”?
A: The feeling was that the jokes fell flat and caused confusion. Those were the only scenes ever edited out for the US market.
Q: Are there any plans for a W.I.T.C.H. movie?
A: There currently are none. The feature film mentioned on movietome is total fabrication.
Season 1 vs Season 2
Q: Why didn’t the US change the opening credits for the second season?
A: Because they wanted consistency in case they aired both seasons simultaneously.
Q: Why do the artwork and animation of Season Two differ slightly from Season One?
A: Different director and animation studio.
Q: Why is it that the second season is closer to the comics than the first season?
A: The writing team felt that the new season required more in-depth exploration of the source material, and drew some inspiration from both sagas 1 & 2 of the comic-books.
Q: What does Will say when she transforms?
A: In the first season it’s just an unintelligible grunt. In the second season, Will audibly says “The Heart” in the first 11 episodes, after which she switches to “Quintessence” once she discovers that power.
Q: Why was Laurent’s name changed to Clubber?
A: Because it was deemed that Laurent was the kind of name a kid would get beaten over at school, and therefore the opposite of a typical bully name. From then on Laurent was therefore referred to by his nickname, Clubber, while his actual full name in the TV series is in fact “Laurent Clubberman”.
Q: Is “Lin” Hay Lin’s last name?
A: “Lin” is both Hay Lin’s surname and the last past of her first name. Since in Chinese culture it’s traditional to put the family name first, Hay Lin’s full name is therefore “Lin Hay Lin”.
Q: Why was Thomas Vandom’s first name changed to Tony?
A: Since there is only one Thomas Vandom existent in real life, Legal strongly advised that we change the character’s first name in the show so as to avoid any implication of personal slander and disparagement.
Q: Where does the name “Trill” come from?
A: It was inspired by comic-book issue #19 in which Hay Lin is haunted by a strange tune known as “Nerissa’s trill”.
Q: Is there a ‘lost episode’ of W.I.T.C.H.?
A: There is an unaired 15-minute pilot episode which was never fully animated and was used back in 2003 to test viewers’ response to the show during a focus group.
Q: Why does Nerissa wear a metal gauntlet?
A: She wears it to hide the Mage Ring underneath so as to avoid blowing her cover as the Mage.
Q: How did Nerissa get hairs from Queen Elyon’s head in “D is for Dangerous”?
A: She got ahold of them when she was posing as Trill.
Q: Why was the order of the transformation sequence changed halfway through the second season?
A: Beginning with episode L, Will says "Quintessence" and gets moved to the end of the transformation order in order to show how Quintessence is the embodiment of the four other powers.
Q: How come Caleb doesn’t have in the show the green stripes he has on his cheeks in the comics?
A: Children in test audiences for W.I.T.C.H. were disturbed by Caleb's face markings, which furthermore would have prevented Caleb from regularly interacting with human teens and adults in the TV series.
Q: Why didn't the girls have some extra powers in the first season which they already had in the comics during the first saga?
A: It’s a matter of showrunner’s discretion. For the first season, A. Nicholls & D. Vickers felt that the girls had too many powers in the comics, which is why they didn’t use most of the Guardians’ secondary abilities.