Dashboards show numbers; a guestbook shows the humans behind them: effort, teamwork and backstage stories.
"Thanks for the teamwork this sprint—we held together."
"This milestone happened because of all the pairing hours."
"Hats off for the quality delivered despite surprises."
Yes, any shareable goal works.
Yes, share the link with whoever should contribute.
Yes, the board owner can remove a message.
Yes.