A Google worker with a fat finger has committed a classic mistake in fast-moving electronic markets: hitting the wrong key during a training exercise, in the process injecting a dummy advert into a huge number of web pages and apps.
The error, which happened late on Tuesday California time, saw the fake advert — a blank yellow rectangle — appear on many websites and in apps viewed in the US and Australia for a period of about 45 minutes.
The failure to prevent such a basic human error is a black eye for Google, which has led the automation of online ad placement and is widely recognised as the leader in applying artificial intelligence to how such markets work.
Google confirmed the mistake on Wednesday and said it would “honour payments to publishers for any ads purchased”. It would not comment on the scale of the problem, but one ad industry source put the potential cost at $10m.
Potential cost of the error estimated by an ad industry source
The mistake happened when a group of Google advertising trainees were being shown how to use the electronic system, said one person familiar with the error. One of the trainees went further than intended and actually submitted a “buy” order. The mistake was not noticed by anyone at Google for three-quarters of an hour, a lifetime in online auction markets, despite the wide reach that the advert was given.
The Google trainee placed orders at as much as 10 times the normal market price for the adverts, said two people familiar with the error. The orders were for more than $25 per CPM, or cost per thousand impressions — far higher than the $2-$4 market price of the ad space.
The vulnerability to a such a basic human mistake shows how trading foibles familiar on Wall Street are creeping into the highly automated advertising business, where large volumes of inventory are bought and sold in real-time with the click of a button.
The advert was placed through Google’s AdX, a so-called programmatic system for buying space in a real-time auction across thousands of websites and apps. The ad was also placed through several exchanges run by other companies. However, it did not find its way into all online ad exchanges — something that would have made it pervasive on the internet during the fateful three-quarters of an hour.
“An advertiser training exercise led to an error where actual spend happened on publisher sites for approximately 45 minutes,” Google said. “As soon as we were made aware of this honest mistake we worked quickly to stop the campaigns running.”
The company said it was looking at putting safeguards in place to make sure the mistake could not happen again.