As of 10/27 the functions of the Chat plugin have been rolled into
tests-passed. Chat will be officially released as part of Discourse v3.0.
You may have noticed Chat recently being added to your community, or here on Meta. In this topic we’ll take a look at the various features included in Chat, and how you can make the most of them!
Types of Chat
Channels
Channels are group chats which can be accessible to all users, or limited to those given access by your community’s admins. A community might have an #off-topic channel available to all users, and a #moderating channel which only admins and moderators have access to.
A channel with new messages will have a colored dot after its name, as seen here;
Personal Chats
You can create Personal Chats by using the 
icon to the right of the Personal Chats header. If using Full-Screen Chat, you will need to hover-over the heading for this icon to appear.
In addition, user cards have buttons to begin chats with that user (both in chat and in topics).
Accessing Chat
The first question some of you have will no doubt be “this sounds great - so how do I use it?” Provided your community has chat enabled, which Meta does, you can tap on the speech bubble icon to the left of the search tool at the top of the page to open a chat window.
Provided you are not using Full-Screen Chat, tapping the same icon will dismiss the chat window. If one or more Channels have new messages, the icon will have a colored dot, like so;
If you have new messages in Personal Chats, the icon will have a green dot.
Online users will have a green border around their avatar, unless this is suppressed due to them having toggled Hide my public profile and presence features in their interface preferences.
Changing Your Chat Preferences
Here’s a link to your Chat preferences, from where you can do the following;
- Toggle whether Chat is enabled for your account
- Disable pings from
@alland@herementions - Change the desktop notification sound
- and more!
Functionality Exclusive to Chats
Full-Screen Chat
The default chat window has a button to expand chat into a full-screen view. This is great for when you want chat to occupy its own tab, rather than being a floating window above other content.
Full-Screen Chat in a pinned browser tab quickly became my favourite way of using Chat!
Joining, Leaving, Muting and Configuring Channels
Tap on the 
icon to the right of the Channels header in the sidebar to view the list of channels you can join and leave. If the icon isn’t there, hover-over the header to force it to appear.
In the view that opens, each channel will have a icon on its card. This can be used to access settings such as muting the channel and configuring desktop notifications for it.
Here are direct links to configure various channels;
The option to leave a channel is presented in the About tab of its settings.
Message Retention
Chat differs from regular topics in that is ephemeral; while a topic might contain important documentation that a community desires to retain for several years, chat works best as short-form communication; e.g. asking how something works, or what information is needed to diagnose an issue.
By default, messages in channels last for 90 days. Note that this can be customised by admins, and so may not be accurate for your community. Personal chats between specific users last forever by default.
Quote In Topic
Have you seen an awesome message in chat you want to share with others?
Just hover-over a message until the menu appears, and then open the kebab menu. This will include an option to Select the post, after which you can use the Quote in Topic button which appears at the bottom of the chat window.
Here’s an example of a chat message quoted in a topic.;
I'd be interested in taking that on! 
Would it be considered good practice to initially post it elsewhere so that others can offer feedback & potentially move the topic if it is considered useful? Or should I just post it there and see how it goes?
Chat messages quoted in topics do not presently display a user’s real name in the way that regular posts do when the site setting to prioritise real names is enabled.
Note: Messages quoted in this manner will persist in the topic indefinitely, even after expiring in Chat itself and no longer being accessible there (which, by default, will happen after 90 days).
Reactions
Where regular posts have likes, chat messages allow for a range of emoji reactions. Let another user know you appreciate their message with a 
, 
, 
, or another emoji of your choosing.
A handful of commonly used emoji are pinned to the menu, however you can tap on the icon to the right of these to show the full range of available emoji. It’s safe to say there’s lots to choose from!
Functionality Shared With Posts and Topics
Bookmarks
It’s possible to bookmark a chat message by hovering-over it until the menu appears, and then tapping on the bookmark icon. Chat messages share the same list of bookmarks as regular posts and topics.
Copy Link
To copy a link to a specific chat message, hover-over it until the menu appears, and open the kebab menu. A Copy Link option will appear, giving you a link like this;
https://meta.discourse.org/chat/channel/129/-?messageId=6579
By default, Discourse will convert such links into oneboxes.
Deletion
Accidentally share a photo of your cat in the wrong place? It happens to the best of us!
Hover-over the message of yours you would like to delete, and from there open the kebab menu & choose Delete. This will cause your message to be hidden by default for you, and hidden totally from other users. You can tap on a hidden message of yours to view it. Opening the menu again will give you the option to restore the message, should you change your mind.
Admins and relevant moderators will be able to expand and see your deleted messages until the retention period (90 days) expires.
Edit
Hover-over the comment you want to edit, and tap on the button to open the kebab menu when the on-hover menu appears. Chat will show that your message has been edited. Neither you nor other users will be able to view the revision history of your message after you have edited it.
Flags
See some unruly behaviour? Has a spambot somehow snuck in? See a photo of a dog when you’re a cat person? To flag a message, hover-over it to display the on-hover menu, and then open the kebab menu to access additional options. 
Flagging the message will be one of them.
Insert Date / Time
The Insert Date / Time tool is available in the toolbar. To toggle the toolbar, just tap on the icon to the left of the text box. Both Simple and Advanced modes are available.
Oneboxes
Links included in chat messages will form oneboxes in the same way as regular posts. Note that clicking on one will, by default, open it in the current tab - this can be a little disruptive if using Full-Screen Chat! Right-clicking on the link at the top of the onebox allows you to open it in a new tab.
Replies
The menu which appears when hovering-over a message allows you to reply to that message specifically - you’re looking for the arrow icon.
Replying to a message shows a small preview of it above your own, which can be interacted with. Clicking on it when the original message is in view causes it to be highlighted briefly. Otherwise, clicking on it will cause chat to scroll up to the message so that you can see it in its entirety.
Here’s how it looks;
Search GIFs
Tap on the icon to the left of the text box to open the toolbar, and then select “Search GIFs” to open a window which will allow you to search GIFs hosted by GIPHY.
Uploads
Open the toolbar by tapping on the icon to the left of the text box, then tap on Attach a file to upload a file such as an image, video, or text file.
Tap here to view a list of supported file extensions
- .AVIF
- .CSV
- .DOCX
- .GIF
- .GZ
- .HEIC
- .HEIF
- .JPEG
- .JPG
- .JSON
- .MOV
- .MP4
- .PNG
- .SGV
- .TEX
- .TXT
- .WEBM
- .WEBP
- .ZIP
User Cards
Just like other parts of Discourse, tapping on a user’s name or avatar in Chat will open their user card. Regardless of where you access it, user cards will feature the option to initiate a Personal Chat with that user, unless they have disabled Allow other users to send me personal messages and chat direct messages in their notifications settings or enabled Only allow specific users to send me personal messages or chat direct messages in the Users sub-section.
Corrections, Additions, and Other Suggestions
Did I get something wrong, omit something, or not phrase something clearly? Something else? Please let me know, or edit the post (it’s a wiki) - together, we can make this topic the best it can be.