RFC 2142 role mailboxes are critical. It's pretty telling that the webhosts that ignore the RFC are the ones I constantly find problems at. Godaddy not only routinely hosts all kinds of evil, but they make reporters jump through hoops to let them know they need to clean up their mess. If you do try to email [email protected] they'll ignore your report and kick back an autoresponder message telling you to fill out a shitty web form instead. Nothing like making more work for people who already went out of their way to let you know you're causing problems for everyone else.