Few publishers have adopted ads.txt because their tech teams are overcommitted to other projects, and they don’t understand how ads.txt will benefit them. Plus, some publishers want to avoid notifying ad buyers that they rely on unauthorized resellers to drive demand for their inventory. Of the 500 most-trafficked sites in the U.S., only 34 use ads.txt, according to a recent analysis by MarTech Today.
The Interactive Advertising Bureau Tech Lab launched ads.txt in May as a tool that can help ad buyers avoid illegitimate sellers that arbitrage inventory and spoof domains. The way it works is that publishers drop a text file on their web servers that lists all the companies authorized to sell their inventory, which allows buyers to check the validity of the inventory they purchase.