The widespread adoption of ads.txt can be a double-edged sword for publishers.
On one hand, ads.txt—an Interactive Advertising Bureau (IAB)-backed text file that lets publishers publicly list all the vendors authorized to sell their inventory—helps publishers take control of their inventory by giving ad buyers a check against domain spoofing and arbitrage. On the other, making simple errors in the text file can lead publishers to miss out on cash.
Among the top 5,000 websites worldwide selling programmatic ads, adoption of ads.txt increased from 8.5% in September 2017 to 51% by the end of February 2018, according to Pixalate. As publishers adopted ads.txt, many made basic mistakes in their text files. These errors can be problematic, since ad buyers and their demand-side platforms (DSPs) are using ads.txt to filer unauthorized inventory across their programmatic campaigns.
The good news for those with errors on their files is that there are free open-source ads.txt normalization maps that list the common alternative names publishers have for vendors in their files. DSPs can use these maps to fix ads.txt data as it comes in, so that if a publisher used a commonly observed incorrect label they won’t be affected negatively.
Digiday – The State of Ads.Txt
Ad Reform – Tips for avoiding common ads.txt problems