What happened to "Advanced" tab
 

"Define rules" once contained an "advanced" tab that allowed a user to write a customized sieve that would return a specific error message to the addresses included in the sieve. Apparently the rejection rules have now gone to "silent only" and no notification at all, custom or otherwise, is returned to addresses that are rejected to inform them that it has occurred.

Does anyone know why this feature was eliminated?? Having "silent only" rejection leaves the sender wondering whether their message was lost or is being ignored. It seems only courtesy to inform them that their message was not delivered.

The ability to bounce back messages to the sender has been removed because it gets abused by spammers. The technical term is backscatter.

http://en.wikipedia.org/wiki/Backscatter_%28email%29

We found that reject rules were causing us to be added to spam block lists as a backscatter generator. This is bad for all the rest of our users.