The level of fraud happening in the ad space from 2013-15 (when I worked in it) was astounding. I saw millions of dollars go up in smoke. AppNexus also recently

The level of fraud happening in the ad space from 2013-15 (when I worked in it) was astounding. I saw millions of dollars go up in smoke. AppNexus also recently said up to 60% of its traffic was fraudulent.