Nick.com's Avatar Index was a large source of canonical information on the World of Avatar, with content contributions from Michael Dante DiMartino, Tim Hedrick, and Joshua Hamilton. The index was removed at some point and is no longer hosted on Nick.com.
The home page of the index was a map, as well as linked to information on waterbending, earthbending, firebending, and airbending. From there, one could cycle through to maps of Book One: Water, Book Two: Earth, both of which depicted the Avatar world, or Book Three: Fire, a map solely of the Fire Nation and set as the default.
On each map, there were several white dots marking where an episode took place. When hovered over, a pop-up with Aang's face appeared that showed the book number, episode number, and episode name to which the dot was linked.
Upon clicking the white button link, a viewer was shown several different flashes of landscape art, and after a short while a page on the episode. There were several sections written on a bar at the top, and when clicked they would lead to a different entry on the appropriate subject as seen in the episode. On the bottom, there was a bar providing links to the pages for all other episodes in the book, as listed by the season and episode number. The last two episodes of Book Three were merged into one page, titled "Into the Inferno" & "Avatar Aang".
This is the default entry that was shown when one clicked the link to the episode. When one visited this page, information on the episode appeared on the left side, while on the right was a picture of Aang and his staff.
Upon clicking the "characters" section, one saw a slider with the faces of several characters seen in the episode. Upon clicking one of the faces, the full body of that character was seen, as well as their name and a brief description of who they are.
When the "creatures" section was clicked, all creature entries on the page were shown, including an image of the creature, their name, and a brief description.
In the "new locations" section, there were images at the bottom of locations visited in the episode. When one of the images was clicked, a larger version of the picture appeared in addition to an entry on that location.
Gear & more
In the "gear & more" section, either objects or other miscellaneous items from the episode would be shown on a slider similar to the one in the "characters" section. The slider was a little larger, however, and the images were of the whole item instead of just a small part of it.
- When one tried to read the pages on water, fire, or airbending, they were cut off about halfway through, even though there was still text left. However, the entry for earthbending could be read in its entirety.
- Several entries were missing the proper information and instead had undefined written in their place. They also had images that flip back and forth between what they should be, and the image from another entry. The proper information for Books One and Two could, however, be examined in coded, undecorated format at the Wayback Machine.
- Chapters three through twenty from the first season were on the Book One map but were listed as Earth in their summaries.
- On the page for "The Southern Air Temple", the image of the air temple sanctuary was one of the Earth Kingdom Avatar temple.
- The episode "The King of Omashu" was titled as "Return to Omashu", which is actually a Book Two episode.
- The episode "The Great Divide" was titled as "Bitter Work".
- The page for "The Blue Spirit" featured General Fong's fortress in the background, which does not appear until "The Avatar State".
- On the page for "The Blind Bandit", The Gopher, and The Gecko were listed under the creatures section.
- On the page for "The Serpent's Pass", the episode's corresponding location was marked as undefined and the image on the link switched between the pass and the waterfall pond.
- On the page for "Appa's Lost Days", the beetle-headed merchants' market was marked as Whaletail Island and the image on the link switched between the market and the Eastern Air Temple.
- On the page for "Lake Laogai", the same picture of the lake was used for Whaletail Island and Lake Laogai.
- Even though there was no page for the "The Runaway", there was a link on the home screen for Book Three and the slider at the bottom of the page.
- On the page for "The Boiling Rock, Part 2", Hakoda's picture was shown on an article about a tough criminal.
- On the page for "The Southern Raiders", instead of a picture of Kya, there was a picture of a Southern Raider. Furthermore, her name was purported as being "Kaya".
- Hawky was incorrectly noted as being in "The Southern Raiders".
- On the page for "Sozin's Comet, Part 4: Avatar Aang", the description for the liberation of Ba Sing Se stated that Iroh and the Order of the White Lotus fought the battle during an eclipse, when it was actually during Sozin's Comet.
- The gear and more section of the entry for "Sozin's Comet, Part 4: Avatar Aang" showed energybending with a photo of Aang firebending. Also, the characters section stated that Ursa was born and raised as royalty, which is inconsistent with her given history.
- A section titled "Katara's diary" was originally present on the episode pages, however, clicking it would lead only to a message stating that its content was coming soon. The section was never updated, and it was eventually removed from the index.