This is the living version of the book's measurement setup. The mechanics below are the parts that date fastest in print: which platforms pass a referrer, which tags to watch, and which trackers are worth paying for right now.
Last updated 23 September 2026Start with what GA4 already does: since May 2026 its default channels include AI Assistant, which groups visits from ChatGPT, Gemini, Copilot and others. Check it first. Build your own channel only if you want every source below in one place you control.
In your analytics, create a named channel called AI Referral and point it at the domains AI tools send from. Left alone, these visits scatter into the general referral bucket among hundreds of other domains.
chatgpt.com and chat.openai.comperplexity.aiclaude.aigemini.google.comcopilot.microsoft.comyou.com, meta.ai, and whatever launches next; recheck this list quarterlyAlso add a filter for utm_source=chatgpt.com. ChatGPT has tagged most cited links since late 2024, and those visits can land in "Unassigned" if your channel rules don't catch the tag.
The click-by-click GA4 steps, including where the channel sits and how to test it, are on the GA4 how-to page.
| Platform | What your analytics sees | Status |
|---|---|---|
| ChatGPT (web) | Referrer + utm_source=chatgpt.com on most cited links | Attributable |
| ChatGPT (apps) | Tagged citation clicks carry the UTM; untagged links arrive naked | Partial |
| Perplexity | Clean perplexity.ai referrer | Attributable |
| Claude | Clean claude.ai referrer, no UTMs | Attributable |
| Gemini | gemini.google.com referrer | Attributable |
| Microsoft Copilot | No referrer since late 2024; lands in Direct | Hidden in Direct |
| Google AI Overviews / AI Mode | google.com referrer; hides inside Organic Search. Use Search Console's AI performance report to break it out | Hidden in Organic |
The book's rule of thumb holds: depending on whose study you read, somewhere between a third and two thirds of AI-referred visits arrive with no source information at all. Whatever your channel report says, it is understating AI's role.
AI visibility trackers run your prompt library across platforms on a schedule and track citation share against competitors. The market moves fast; this shortlist reflects what we run and see working as of the date stamped above.
Corrections, renamed products, and moved pages live in the reader hub's Updates panel, alongside all 18 chapter skills, including the AI Visibility Dashboard skill that assembles this whole setup for your site.