When ending a MarketPlace listing successfully, Pinsiders can invite user feedback from the other party. Marketplace feedback cannot be removed, but can be responded to by mario_1_up.
New! It is now possible for any Pinsider to leave feedback, without an invite. There are some checks in place to avoid abuse and "fake" feedback.
“Bought a player pinbot from mario_1_up.
He knows what he’s doing because the game plays flawlessly. Would do business with again!”