Spammers are using davidchart.com addresses in their From: field again at the moment, so I’m being flooded with undeliverable message responses from really, really stupid MTAs. My junk mail filters are being pretty good at picking them up, but if I send an email to you and it really bounces, I won’t know. (I’m getting over 300 bounce messages per hour.)
In the past, they’ve moved on to other addresses fairly quickly (don’t annoy anyone enough to make it worth their while to go after you…), but if they don’t I might have to set my account to discard anything from mailer-daemon or postmaster, in which case I simply won’t see any warnings or undeliverable message notifications.