+
+
+ The ads.txt specification
+ provides a way to list the authorized sellers of ads for a domain. The
+ app-ads.txt specification
+ extends this to cover apps tied to the domain. As a domain owner, this is a valuable
+ way to crack down on fraudulent usage of your domain including by adware.
+
+ For domains without any third party advertising including those without any ads at
+ all, you should serve both /ads.txt and /app-ads.txt from a
+ web server with the placeholder record defined by the specification:
+
+ placeholder.example.com, placeholder, DIRECT, placeholder
+
+ The placeholder record formally disallows buying and selling ads on behalf of the
+ domain including for any subdomains. This prevents fradulently buying / selling ads
+ for your domain anywhere that ads.txt / app-ads.txt are enforced.
+
+ It's in the interest of most ad tech companies to enforce these standards due to
+ losses from ad fraud so adoption is increasingly widespread.
+
+ Browser extension malware injecting ads into sites is very common and this is a way
+ for sites to hurt those malware developers where it hurts: their pocketbook.
+
+ These standards have a limited scope and were primarily created to address the cost
+ of ad fraud for the advertising industry, but they do offer value for domain owners to
+ protect their reputation and discourage adware.
+
+