Closed Mailbox With Raised Flag on Threads

What it signals here

thread context

Used to open or close threads about communication, waiting, or sent messages.

reply use

Dropped in replies to indicate 'I already messaged you about this.'

trending meaning

Surfaces in trending conversations about ghosting, waiting on replies, or big announcements.

quote use

Used in quote posts to say 'the flag has been up, time to respond.'

See it elsewhere