Like so many standards, ads.txt didn’t catch on right from the beginning. One definite reason for its initially restrained use in the industry was uncertainty: How would the file influence individual businesses? It was only when the heavyweight Google started supporting the initiative and insisted on using the file from that point on that ads.txt gradually prevailed.
One point that has created uncertainty within the industry is that resale of inventory is somewhat complicated. Providers buy advertising space from a platform and sell it on their own. This isn’t always fueled by criminal intent, but ads.txt prevents such behavior. Publishers have no direct connection with these resellers and often know nothing about the processes. As a result, the provider doesn’t appear in the ads.txt file. This has caused some resellers to target publishers, which in turn has generated a lot of discussion within the industry and is seen by many as an attempt at fraud.
A point of criticism for many sellers is the manual creation of the file: it’s not guaranteed that there are no typos. An error can quickly creep into the domain name, and then the publisher’s inventory can no longer be traded on the platform. This can cause both the seller and the publisher to miss out on large sums of money. The use of an ads.txt validator, though, can significantly reduce the risk of typos, while checking whether the domain is concealing a programmatic advertising marketplace. And ultimately, typos can also be avoided through careful attention to the process.
Another weakness of ads.txt is the missing tagging of the type of agreed upon inventory: publishers can’t use the text file to signal whether the seller may sell display ads, video ads, or both. This means that platforms can continue to pretend that display ads are actually advertising space for video ads, and so receive additional commissions. Just because a seller appears in an ads.txt, it’s still not guaranteed that they’re legitimate. The responsibility for not entering into an agreement with scammers lies solely with the publishers.
You should also consider that ads.txt isn’t an all-purpose solution. Sure, you can protect yourself very well against domain spoofing with the file, but other forms of ad fraud remain unaffected. The admittedly laudable initiative still can’t put a stop to the fraudulent tricks of impression fraud and click fraud, which still cost advertisers a large portion of their advertising budget.