If you are in the business of parsing and processing email Feed Back Loop (FBL) messages, you may want to read this about the AOL proposed standardized format.
I guess this is good news in the way that hopefully a standard will emerge, but I'm not sure that AOLs proposal is best. My main problem with it is that they intend to redact the email address. That just further complicates the process of flagging the account in your database (time to re-examine the X-Header drawing board). I mean, they are ONLY sending these FBL messages back to a whitelisted sender so what is the paranoia of an email address or screen name getting hijacked?