The Chat Room is where select inhabitants of Ikebukuro discuss rumors and happenings in the city. It frequently appears in the anime and light novels whenever any of its members log in to chat.
Differentiation from the Dollars Site
The Chat Room is not to be confused with the Dollars site, which has a home page bearing the name 'Dollars' and is accessed through the password 'Baccano' (a reference to another work in the Naritaverse). Unlike the Chat Room, the Dollars site hosts forums where all members of the Dollars can post. Because the anime shows the Chat Room much more frequently than the Dollars site, but the Dollars site is mentioned much more frequently by name, they are often confused for one another. In season one of the anime, the forums were where Mikado expressed his opinion that the Dollars can do some good in the world, motivating some members to clean up city graffiti. The Dollars forum was also shown when Mikado read about people wanting to quit the gang when their group started getting attacked by the Yellow Scarves. Later on, the Dollars site was also used to help Anri Sonohara escape the Yellow Scarves.
The Dollars are the subjects of several Chat Room conversations, further illustrating their existence as a separate online group. In chapter one of the eighth light novel, the newest Chat Room members ask each other if they are members of the Dollars, suggesting that the two sites are not related, though many Chat Room users do happen to be members of the Dollars due to the fact that they live in Ikebukuro.
As the Chat Room and Dollars website exist separately, people without an account on one site may still be a member of the other. Kyohei's gang are examples of Dollars members who do not participate in Chat Room conversations. Those who have membership on both sites, however, may use different handles. Izaya Orihara sent a message to all the Dollars as 'Nakura' during the arc with the Toramaru gang, but he goes by 'Kanra' and poses as a girl in the Chat Room. Aoba Kuronuma's handle in the Chat Room is 'Pure Water 100%,' but his handle on the Dollars site is 'Young Leaf Mark.'
About the Chat Room
The Chat Room seems to require a special invite, as Izaya shows surprise when his sisters appear on it. It is later revealed that Namie, who also knows of the Chat Room and watches it but doesn't post on it, was the one who gave them the site address.
Izaya is the Chat Room admin who operates under the alias 'Kanra'. Kanra is first suggested as being the creator and admin when she blocked 'Saika's' IP address after Saika started spamming the room during the Saika Arc. Kanra stated that Saika still kept reappearing to spam the room using various other IP addresses, so blocking them was pointless. Kanra's role as the room admin was also mentioned in the prologue of volume eight of the light novels. It seems Kanra's permission is not required for others to join in the chat as long as they have the site address.
Chat logs similarly seem to be view-able by anyone at any time without Kanra's permission. Private mode may also be initiated between any particular users, though it has been shown at least twice that new users have a hard time figuring out how to respond in private mode instead of public mode while viewing the former.
It appears that users can take on others' handle names in the Chat Room and that Kanra being the admin has the ability to delete previous Chat Room records. However, both of these abilities may be specific to Kanra only as the administrator for the chat. At one point, Izaya took on Kida's handle, 'Bakyura', to talk to Mikado with the implication that he was Kida. He also deleted the Chat Room records so that Kida wouldn't find out that his handle had been used without his permission and that he had been impersonated.
Frequently Seen Users
Mikado Ryuugamine as Tarō Tanaka (田, Ta) in dodger blue
Celty Sturluson as Setton (セ, Se) in gray
Izaya Orihara as Kanra (甘, Kan) in yellow-orange, and (ク, Ku) Chrome in violet.
Anri Sonohara as Saika (罪, Sai) and Tsumiuta in red
Masaomi Kida as Bakyura (バ, Ba) in neon green
Kururi Orihara as Kyo (狂, Kuru) in deep sky blue
Mairu Orihara as Mai or San (参, Mai/San) in blue
Mizuki Akabayashi as Gaki (餓, Ga) in green
Eijirou Sharaku as Sharo (し, Shi) in baby blue
Saki Mikajima as Saki (サ, Sa) in yellow
Aoba Kuronuma as Pure Water 100% (純, Jun) in brown
In the Anime
Episode 01: TanakaTaro tells the others that he moved to Ikebukuro that day. Kanra suggests meeting up and talks about an urban legend called the Black Rider. TanakaTaro mentions seeing the Black Rider on his first day in the city. Setton says she was there, too, and TanakaTaro wonders if they passed each other on the street without knowing it.
Episode 02: They talk about suicide groups and people going missing around the city.
Episode 03: Setton and Kanra warn TanakaTaro to stay away from a gang called the Dollars.
Episode 04: They talk about the Black Rider not having a head. Setton finds the idea ridiculous, TanakaTaro is intrigued, and Kanra tells them that the Black Rider is not human.
Episode 05: A new member appears, posts disjointed words, and leaves quickly. Kanra later tells the others than she banned the troll and shares rumors about members of a group called the Yellow Scarves being attacked by they city's serial slasher, ignoring TanakaTaro's questions.
Episode 06: Kanra talks about foreigners and immigrants going missing in Ikebukuro, and TanakaTaro says that a classmate of his has gone missing. Kanra suggests that the Dollars may have eaten the missing foreigners.
Episode 08: They talk about losing things and about dreams.
Episode 12: Kanra does not come online, and Setton has to leave before she is able to converse with TanakaTaro.
Episode 13: The members talk about the increasing presence of the Yellow Scarves around the city. A troll called Saika enters the Chat Room and repeats the word 'cut.' Kanra claims to have repeatedly tried blocking Saika's remote host, but they keep coming back.
Episode 15: Kanra tells the others about the latest slasher victim. Saika enters the chat, repeating the word 'cut.' Their disconnected words are turning into almost coherent phrases. Setton tries to make conversation, and TanakaTaro wonders if Saika could be the slasher. Saika repeats the name Shizuo Heiwajima until they abruptly exit the chat room.
Episode 16: Setton logs in to see disjointed sentences and an offer from Saika to wait for Shizuo at South Ikebukuro Park.
Episode 17: Saika apologizes for the trouble she caused for the other Chat Room users. The members welcome her warmly.
Episode 19: Kanra shares rumors about growing tensions between the Dollars and Yellow Scarves over the slasher incident. In PM's, Kanra shares with TanakaTaro the history between the Yellow Scarves and the Blue Squares and suggests the possibility that the slasher might be working from within the Dollars.
Episode 20: Kanra continues gossiping about growing tensions between the Dollars and Yellow Scarves.
Episode 21: Setton tries to reassure Saika through PM's that certain events are not her fault, but Kanra shares more rumors about the increasing gang violence in the city. Saika cannot figure out the PM system and responds to Setton in the general feed.
Episode 24: Bakyura introduces himself to the other members.