The rule is you quote what has gone before and add a new simple message. And so the log grows.
Edit note:
The original plan was that the server would allow you to quote the previous quote and so on to create a many ringed effect - like a sawn log. However, I didn't research the server sufficiently. It deletes the previous quote. Hey Ho.
Plan B then - add your greetings as you wish in a normal thread way - it can still be a "log" by being a long list of greetings.
Edit note:
The original plan was that the server would allow you to quote the previous quote and so on to create a many ringed effect - like a sawn log. However, I didn't research the server sufficiently. It deletes the previous quote. Hey Ho.
Plan B then - add your greetings as you wish in a normal thread way - it can still be a "log" by being a long list of greetings.