As digital advertising continues to grow, so does the opportunity for fraud. Marketers who are paying for online campaigns want to know that fraudtheir ROI metrics are based on solid numbers. But, new studies show that bots are at work in online ad exchanges and marketers may need to rely on specialty firms to help them detect and avoid paying for ‘fraudulent traffic.’

New research released by tech firm Spider suggests that advertisers are being bilked out of $6 million a month by paying for ad that are shown to bots instead of real people. In this case, the bots are a network of 120,000 Windows-based, infected computers in the U.S.  Ad exchanges are growing more popular as a destination where marketers and publishers meet to buy and sell online ads. Because the process is so automated, analysts say it’s been easy for criminals to infiltrate the networks and serve up ads to ‘ghost sites.” Analysts believe the bot operators are making money by showing retargeted ads. They can follow legitimate users as they move from site to site. Using stored information, they serve up a retargeted ad on non-legitimate sites to the bot instead of the consumer and the publisher pays for it.

Experts believe that publishers and exchanges alike bear responsibility for detecting and rooting out bot operators. Companies like DataXu talk about efforts to “clean our supply chain and build our forensics capabilities from day one.” As marketers are evaluating how they’ll place their online ad campaigns, they’ll likely start asking publishers to prove that their inventory is clean. They’ll also want network operators to prove the sites where ads are appearing are legitimate.

Have you encountered fraudulent clicks in your ad campaigns?

[Sourcs: Roberts, Jeff John. Massive bot network. Paidcontent.org. 19 Mar. 2013. Web. 8 Apr. 2013; Rodgers, Zach. How Buy-side Platforms are Fighting Online Ad Fraud. Adexchanger.com. 1 Apr. 2013. Web. 8 Apr. 2013]