Closed Mailbox With Raised Flag on Facebook

What it signals here

reaction meaning

Rarely used as a reaction; more often typed in comments to point someone to their inbox or messenger.

comment use

Commenters use it to say 'I sent you a message on Messenger, please check!'

boomer interpretation

Older users interpret it literally as a physical mailbox and may use it in contexts about actual postal mail.

group use

Group admins use it to remind members to check group announcements or private messages.

See it elsewhere