Last updated: 2 July 2025
Scammers are increasingly using no-cost conversions—like fake leads or add to carts—to disguise fraudulent ad clicks. This tactic tricks advertisers and advertising networks into misjudging bot activity as legitimate traffic, wasting ad budgets and time.
What is click fraud?
Before diving into how scammers use no-cost conversions to exploit advertisers and ad networks, it’s important to understand what click fraud is.
Click fraud is a form of digital advertising fraud that costs advertisers billions each year. It exploits the pay-per-click (PPC) model by generating fake clicks through bots rather than real users, resulting in massive volumes of fraudulent traffic.
Based on Polygraph data, at least 8% of all ad clicks are fake. In high-value verticals like finance, medical, and legal, the fraud rate can climb as high as 80%.
Here's how it works:
- A scammer—someone who understands how PPC advertising functions—creates a website and applies to join an advertising network like Google Ads or Microsoft Ads as a publisher. Once approved, they can host ads from legitimate advertisers on their site.
- Rather than wait for real people to visit and interact with those ads, the scammer uses bots to generate clicks. These bots are disguised to look like legitimate users: their traffic is routed through residential and cellphone proxies, giving them unique, normal-looking IP addresses, and their device fingerprints are forged. This makes detection by ad networks extremely difficult.
- After clicking on an ad, bots will often go one step further and trigger a no-cost conversion on the advertiser’s site—such as filling out a lead form, signing up for an account, or adding an item to a cart. This creates the illusion of valuable engagement and tricks ad platforms into thinking the click came from a real, high-quality user. Meanwhile, advertisers waste time and resources following up on fake leads. A nasty side-effect of these fake conversions is they train the ad networks to send even more bot clicks, since their algorithms optimize based on your site's conversions.
- Because ad networks typically struggle to identify even basic forms of click fraud—and are easily misled by fake conversions—advertisers end up paying for the fake clicks. The resulting revenue is shared between the ad networks and scammers, often in a roughly equal split.
- Polygraph currently tracks thousands of scammers earning more than USD $1 million per month per site through this scheme. Many operate multiple fraudulent websites simultaneously.
There are various versions of this scam, including retargeting click fraud, which takes advantage of advertisers’ follow-up campaigns to repeat the deception.
What is conversion fraud?
Click fraud bots don’t typically make purchases, which can make their traffic appear low quality to ad networks. If left unaddressed, this could get a scammer’s publisher account suspended.
To avoid this, scammers program their bots to occasionally generate fake conversions — like submitting lead forms, creating accounts, or adding products to carts — after clicking on ads. These fake actions boost the scammer’s traffic quality score and help the bot traffic appear more human by mimicking real user behavior patterns.
Why do bots target no-cost (free of charge) conversions?
No-cost conversions, like submitting fake lead forms, are easy for click fraud bots to generate. The bots simply locate lead forms on advertisers’ sites and fill them with bogus data—often using real people’s information. When advertisers follow up, they usually encounter confusion or dead ends, as those leads aren’t genuine.
Attempting paid conversions—such as making purchases or subscribing to services—would raise scammers’ costs and require managing valid payment details. In contrast, no-cost conversions are free and straightforward to produce.
Why aren't the advertising networks detecting click fraud and fake conversions?
This is the multi-billion dollar question. Despite being a relatively small company, Polygraph can detect the vast majority of click fraud, while many advertising networks still struggle, sometimes failing to identify even the simplest fraudulent clicks.
One view is that advertising networks have a conflict of interest, as they earn revenue from every click—whether genuine or fake. More likely, the issue comes down to insufficient effort and attention from the teams responsible for detecting and preventing click fraud.
How do I prevent fake conversions?
Since conversion fraud is a direct result of click fraud, the best way to stop it is to prevent bots from completing fake conversions. Polygraph blocks bots from submitting lead forms, creating accounts, or adding items to carts — ensuring that only real humans can generate conversions on your site.
Because advertising networks optimize ad delivery based on who converts, stopping bot conversions helps retrain their algorithms. With only human conversions coming through, the networks start showing your ads to more real users and fewer bots. Eventually, bots stop seeing your ads altogether—so nearly all clicks come from genuine people.
These clicks also tend to be high quality, since they come from users who resemble the real humans converting on your site.
Polygraph also provides detailed insights into every fraudulent click, including the reason it was flagged, helping you claim click fraud refunds from your ad networks.
In summary
Click fraud scammers create fake conversions on advertisers’ websites to trick advertising networks into thinking their bot clicks come from genuine users. They rely on no-cost conversions, like submitting lead forms, because these are much easier than paid conversions such as product purchases.
Since conversion fraud happens after click fraud, stopping click fraud is essential to prevent conversion fraud. Polygraph provides all the tools you need to detect and block click fraud effectively.