Undocumented Feature
Undocumented Feature
[A support window is shown.] An old Windows utility has an undocumented feature. If you open "help" and click on the background, you get dropped into a "support" chat room. Support Window: Launching support forum...
[An active conversation between two people is shown.] Only a few of us ever found it. But we became friends.
[Cueball and Ponytail are at computers.] We kept launching the program to check in. Eventually some of us were running VMs just to keep accessing it.
[Another conversation.] As the Internet aged, so did we.
[Three question marks.] We don't know who runs the server. We don't know why it's still working so many years later. Maybe we're some sysadmin's soap opera.
[A group of people are shown in a bubble.] It will probably vanish someday, but for now it's our meeting place. Our hideaway.
[The bubble is now smaller, and some parts of a web are shown.] A life's worth of chat,
[More of the web is shown.] Buried in the deep web.
[A flat landscape is shown with the sun at the horizon.] But even if it lasts forever, we won't. When we're gone, who will remember us?
[Cueball and Hairy are shown standing together in a bubble.] Who will remember this strange little world and the friendships we built here?
[No panel shown:] Nobody.
[An empty bubble is shown.] This place is irrelevant. Ephemeral. One day it will be forgotten.
[The bubble starts to fade away.] And so will we
[The bubble has almost completely faded away.]
[The bubble is now completely gone.]
[Caption inside a new panel:] But at least it doesn't have fucking video ads.
There are many examples of undocumented features in programs written for old versions of Windows, for example:

An undocumented feature is a part of a software product that is not explained in the documentation for the product. Cueball has found such a feature, a chat room intended to ask for help, accessible through the help page of some unnamed old Windows utility. The people who found the chat room started out using it for its intended purpose (helping users of the utility by contacting other users), however as time has passed they have become friends and enter the chat only to talk to each other, with no relation to computer problems.
A virtual machine (or VM) is a computer program designed to emulate the hardware of a full computer. In this case, users of the old chat room create VMs only to have the old operating system installed which included the utility program. They use this setup only to access the old chat room. This is shown in the third panel where Cueball is using a modern laptop to enter the chatroom (presumably by means of a VM), whereas Ponytail is most likely using an old computer (as evidenced by the CRT monitor).
A chat room like this must be hosted on some outside server, so the narrator of the comic wonders who runs this server. An obvious thought about this is if and when the server will be shut down, effectively cutting all communication among chat users. Another obvious thought is why the utility author is still maintaining the chat server, since its original purpose of allowing communication between users with problems with the utility program is no longer an issue as everybody has migrated to more modern systems. The comic suggests that the reason for doing this can be a bored sysadmin , who is just reading the messages of the chat users and following their lives but never writing anything. This would turn the chat room into a soap opera for the sysadmin.
The Deep Web is a term used to refer to any information which is available online, but is hard to find (usually because there are no links to that information in web pages). The chat room described would be an example of this. From this point on, the comic takes an existentialist turn (a frequent xkcd trait), talking about how life is short, everything has to end, etc.
The last panel is a reference to Facebook's recent announcement that it would start autoplaying video ads, and the title text refers to YouTube requiring its users to use their real-life identities instead of just nicknames. These last parts of the comics somehow reveal that the point of the whole comic is just to complain about aggressive money-driven policies used by modern social networks in general and Facebook in particular. It is hinted that Randall would prefer older technologies, where limited resources would forbid autoplaying videos or huge databases with every detail of every user's life.
It's possible that the comic is about an actual chat room, but more likely it is a complete invention, since if it were real someone would have been able to trace its origin. However, if it is real, the participants would not want to confirm this in order to protect their privacy.
The title text mentions the simplicity of this chat; even user names do not exist and other users could only be identified by their behavior because the user names are random and can change on every login.
[A support window is shown.] An old Windows utility has an undocumented feature. If you open "help" and click on the background, you get dropped into a "support" chat room. Support Window: Launching support forum...
[An active conversation between two people is shown.] Only a few of us ever found it. But we became friends.
[Cueball and Ponytail are at computers.] We kept launching the program to check in. Eventually some of us were running VMs just to keep accessing it.
[Another conversation.] As the Internet aged, so did we.
[Three question marks.] We don't know who runs the server. We don't know why it's still working so many years later. Maybe we're some sysadmin's soap opera.
[A group of people are shown in a bubble.] It will probably vanish someday, but for now it's our meeting place. Our hideaway.
[The bubble is now smaller, and some parts of a web are shown.] A life's worth of chat,
[More of the web is shown.] Buried in the deep web.
[A flat landscape is shown with the sun at the horizon.] But even if it lasts forever, we won't. When we're gone, who will remember us?
[Cueball and Hairy are shown standing together in a bubble.] Who will remember this strange little world and the friendships we built here?
[No panel shown:] Nobody.
[An empty bubble is shown.] This place is irrelevant. Ephemeral. One day it will be forgotten.
[The bubble starts to fade away.] And so will we
[The bubble has almost completely faded away.]
[The bubble is now completely gone.]
[Caption inside a new panel:] But at least it doesn't have fucking video ads.
There are many examples of undocumented features in programs written for old versions of Windows, for example:
