Robin Sloan argues the Referer header is largely obsolete since most traffic now arrives from email and apps that strip it, making UTM query strings a practical substitute.
Key Takeaways
The majority of web visitors follow links inside email or apps like Instagram, iOS Messages, or Substack, none of which set a Referer header.
This collapses most traffic into a “Direct/Unknown” bucket, making referral analytics unreliable without custom query strings.
Sloan appends utm_source=Robin_Sloan_sent_me to outgoing links as a courtesy signal so site operators can identify and contact the traffic source.
Some sites, including YouTube, break on unexpected query strings, requiring a per-site exceptions list.
Chris Morgan’s choice to reject URLs with query strings is valid, but the premise that Referer absence signals user intent no longer holds for most sites.
