This document discusses how ad fraud harms good publishers in several ways: 1. Ad revenue is diverted away from good publisher sites as bots visit to collect cookies and then visit fake sites to generate fraudulent ad impressions. 2. Profit margins of good publishers are depressed as media agencies seek out low-cost ad inventory, including fake inventory from fraudulent sites. 3. Fake sites pretend to be good publishers and sell premium audiences and inventory that don't actually exist.