In channels with at least six members, Slack will ask you to confirm before you send a message with any of these mentions. Owners and admins can turn this warning off.
On the Enterprise Grid subscription, these mentions work differently in channels. If there are fewer than 10,000 members, only owners and admins can use @channel and @here. If there are 10,000 members or more, no one can use @channel or @here. In default org-wide channels, no one can use @everyone, @channel or @here.
We suggest using these mentions sparingly. If you need to get the attention of someone specific, you can mention that person directly. On the Standard, Plus and Enterprise Grid subscription, you can also notify a specific group of people by creating a user group.
Note: Owners and admins can choose to restrict permissions for who can use @everyone, @channel and @here. If you don’t have the option to notify a channel or workspace, find an owner or admin and ask for help.
@everyone can only be used in the #general channel, which is a channel that all members (except guests) are automatically added to. This mention will notify everyone in the #general channel, whether their availability is set to active or away.
When to use @everyone
Give your organisation information about a new holiday policy.
Alert everyone in the company about an emergency evacuation drill.
Note: By default, guests aren't able to use @everyone.
Use @channel to let everyone in a channel know about timely, relevant information. This will trigger a desktop or mobile notification for all members of the channel, whether their availability is set to active or away.
When to use @channel
Update your team about a last-minute change to a project deadline.
Let members know when you adjust a work process or the channel structure.
Tip: If you're building a Slack app that can notify members, the message from your app's bot user must contain <!channel> or <!everyone>.
Use @here when you only need the attention of people who are actively working in any channel that you’re a member of. This is great for when you don’t want to notify teammates who aren’t available at the time.
When to use @here
Schedule an impromptu event, like a lunch outing, for people who are available.
Get a question answered quickly by teammates who are working.