Bookmarking messages makes them easily accessible via a bookmark icon above the text box.
To bookmark, click the three dots next to a message, and select "Bookmark Message".
Bookmarked messages can be useful for special announcements, kind words from your visitors, funny remarks, handy reminders and so much more.
Bookmarked messages will not be automatically cleared out like other old messages are.
You also have the option of setting which rank is able to bookmark messages -- it is allowed for owners only by default.