Last weekend we added ips.backscatterer.org to our DNS RBL'S. This morning I was alarmed by the fact the Comcast and Gmail were both being blocked. Several of our users started complaining that they weren't receiving emails from people in the Comcast & Gmail network.
My question to all of you is - Have you tried adding this RBL to your list and have you had the same complaints?
Perhaps my kill ratio is set to high to have that RBL running? My current setting is 85 Kill percent & 5 Tag percent.
For me being the admin I thought wow this great! My spam was reduced almost instantly but on the other hand my users were not happy. I'm very interested in getting your feedback how you manage your spam?