Massive drops in CPC across Google AdSense caused a surge of panic among publishers. The decline was first noticed on August 5, causing a chatter in Twitter, Google AdSense Help, and WebmasterWorld.
The cause is not a reporting glitch or interface bug, Google has confirmed, but ad buyers that were exploiting the ad system. Google has promptly blacklisted the culprits.
In a statement given to Search Engine Land, Google acknowledged the issue of declining cost-per-click ads on a publisher’s website and identified the cause of the problem. “Several ad buyers were using irresponsible campaign parameters, lowering query coverage for specific creative types in some countries.”
Following blacklisting guilty publishers, Google said that coverage in the AdSense Account for impacted publishers should be back to normal.
The decline in CPC was due to ad buyers manipulating Google’s ad auction platform, which caused a drop in fill-rate and ad coverage. CPCs dropped so low for some publishers, between 50% and 70% for the past 2 to 3 days.
What makes the drop confusing is that CTR and web traffic remained the same.
It is unclear why some ad buyers exploited the ad system, but the irresponsible campaign parameters they used enabled them to lower query coverage. It is likely that the goal was to inflate click-through rates artificially.
Reasons to get blacklisted from Google AdSense
As listed in the Google Advertising Policies Help, there are many ways an ad publisher can end up abusing the ad network. With a commitment to provide safe, relevant, useful, and varied ads to users, Google strongly suggests avoiding the following in your ads.
- Malicious or unwanted software that may allow some ad publishers unauthorised access to a network, computer, or device.
- Gain an unfair traffic advantage in the auction by promoting the same content from multiple accounts for the same queries, for example.
- Circumventing the system through practices that interfere or exploit the advertising processes and system that Google has set. These include cloaking and manipulating ad text.
- Using practices that violate Google’s Webmaster Guidelines, such as keyword stuffing, spamming social network sites, and sneaky redirects.
Google has specified that, in the event that an ad publisher is guilty of violating the ad policies, their sites and apps will be suspended and advertisers no longer allowed to advertise with Google.