Erm.. didn't Paul create MAPS to explicitly provide - and later monetize - the RBL? Wasn't the RBL a "directory service"? Didn't it map IPs to policy-based information?
MAPS was created to stop spam. Monetizing it was a late necessity due to the need to pay lawyers, but I'm still down about USD 1.0M.
We mapped IP's to policy based information, using DNS to deliver that data. All DNS responses issued by our DNS servers were absolutely factual in the policy they expressed.