Zero-click is not a new phenomenon — it has been around since the featured answer boxes — but AI summaries moved it into a different order of magnitude. The user gets the answer on the results page and has no reason to go any further. More than two thirds of searches now end this way.
The numbers are uncomfortable, but they are accurate. According to one independent behavioural study, one percent of users click a source inside an AI summary. Appearing as a source therefore brings almost no traffic in itself — its value is in the visibility and the credibility, not in the click.
The most common misconception is that you can defend against this with technical tricks. You cannot: it is user behaviour that changed. What you can do is change what you measure — if you carry on counting visitors only, you get a false picture of your own results.
The numbers, and what can be done with them, are the subject of Zero-Click Search: What Happens to Your Traffic, a separate article. Directly related terms: GEO, AEO and machine-readable.