Apparently some mail servers/spam appliances are using a Cisco service that monitors email and web traffic. http://www.senderbase.org/ punch in your IP and find out what they think of you…. I have yet to figure out what to do about things like a “Neutral” rating which apparently will get you bounced. (Please add any info if you find it) Also, there is the ability to search by domain but it yields less useful info.
