Wonder has a robust chat system. There are three ways to use it.
"Circle": A message is only seen by the current circle you are in.
"Private": A message is only seen by sender and receiver.
"Everyone": A message is sent to everyone in the room.
If you leave one Wonder room for another, you will be able to see only your "Private" message history.
Only the people in the room/circle at the time of the message being sent will see the message.