I talked before about the problem with bounce messages (the technical term is Non-Delivery Reports or NDRs) filling people's inbox.
The good news is that we've set things up so that these will now be caught by the spam filters.
The bad news is that any legitimate NDRs will also be caught by the spam filters. If you send a message and get the address wrong you will not get a direct notification.
You can check by logging on to Postini and checking your quarantined messages for those you tried to send. The messages will also be listed in your daily span quarantine report.
I wish there was a way to differentiate between spam NDRs and legitimate ones, but the computer had no way to accurately determine what is good and what is bad. Since the problem with NDR spam is a major one, that's what we fixed, even though it has its downside.
Security and convenience are always a balancing act: how to provide security without sacrificing convenience is something we wrestle with all the time.