Once yesterday and twice today I’ve had emails bouncing back from clients stating my IP address was on a blacklist. The list in question is relays.ordb.org. Problem is that this spam database was shut down in December 2006. According to an article on Slashdot, the ORDB service began returning false positives 3/25/2008 as a way to force administrators to reconfigure their email servers and remove the ORDB service. The arstechnica forum is abuzz with reports about this from different administrators as well. So if you seem to be receiving less email than normal, ask your network administrator to see if you’re still using the outdated spam database.