Am I likely to see a reduction of spam that slips by SpamAssassin?
Unlikely. WELL tests show that better than 95% of the messages that would be blocked by the SBL are already marked as spam by SpamAssassin. For most people, this probably translates to one or two messages a week that would have shown up tagged as suspected spam, but are instead bounced. We expect the decrease in our mail processing load, however, to be significant.
