Stack Overflow and Meta Stack Exchange each have their own chat; the rest of the network (Stack Overflow in non-English languages, Super User, Server Fault, Stack Exchange 2.0, etc) has a combined chat site (Stack Exchange chat). Privileges apply based on your total reputation on the associated site(s):
- On SO and MSE chat, privileges apply based on your reputation or moderator status on the associated site.
- On the combined Stack Exchange chat site, privileges apply based on your total reputation over all sites. If you have the global association bonus rights, only accounts where you have at least 200 reputation count towards this sum, though all reputation (including bonus rep) on those sites count.
The privilege levels are:
- public: read messages in non-private rooms
- registered: talk in any room if invited
- 20 rep: participation (specifically, talking)
- 100 rep:
- bookmark a conversation
- create a public room
- 1000 rep:
- create a gallery room, i.e., a room where messages are public but only specific users can talk
- be able to change the access level of a room where you're a room owner from public to gallery and vice versa
- 10k rep:
- be notified of spam/offensive flags (the number of active flags appears in a circle on your gravatar)
- view deleted rooms (read access only if allowed).
- room owner:
- edit the room name and description
- pin a message (a pin is a super-star)
- remove stars from messages
- grant explicit read or write access
- change the access level of the room from public to gallery and vice versa (only if you have 1,000+ rep or are a moderator)
- grant and remove room ownership
- create and remove feeds
- move messages to a different room
- schedule events
- kick-mute users
- put room in timeout (must specify a reason)
- ♦︎ moderator (on chat.SE, moderator on any site, even SO or MSE; your parent site must be set to one where you're a moderator):
- all the above[1]
- edit or delete any message at any time
- view moderator flags
- mark flags as valid or invalid
- ban users from chat
- annotate users
- delete or destroy chat users[2]
- anonymize a user's messages to their user ID[2]
- put a room in timeout without having to specify a reason
- freeze/unfreeze room
- delete/undelete room, list deleted rooms
- be immune to being kicked or suspended from chat
- remove the restriction on creating new rooms for a user who has been kicked three times
- view a list of recent chat flags raised across all rooms
- ♦︎ moderator on the site associated with the chat room[3]:
- create private rooms (where only specific users can read content)
- see and access private rooms
- change the access level of the room from public or gallery to private
- change which site is associated with the room
- view which user raised a spam/offensive flag on a message (provided that the moderator is in the room where the flag was raised and viewed the flag while it was active)
[1] When moderators create a scheduled event for the chat room associated with the SE site where they are moderators, the event will be published also in the main site.
[2] Moderators can only take these actions on users who've posted fewer than 1,000 messages. For users who've posted 1,000 or more messages, only Stack Exchange developers can take these actions. Developers also have access to a modified anonymize messages tool that removes the user's ID from public view.
[3] For rooms which don't have a parent site set (i.e. are general network rooms), being a moderator anywhere on the network will give you these privileges there as well.