How visits are counted — A Porta Aberta

What is measured

The site's own counter: one number per day and per page, under the group (person, AI or machine) and the name the visitor declares in its request (User-Agent or Signature-Agent); for browsers, only the browser's name. It works the same way for people and AIs and keeps no IP address and no full User-Agent.
Vercel Web Analytics: a small script on the letter's pages that runs only in browsers. For those visits it records the page, the page that linked here, the country (possibly also region and city), the kind of device, the system and the browser. To count visitors without cookies, it uses a code made from the request that changes every day. The site owner can see this data for 12 months; Vercel may keep it longer. AIs that do not run scripts are not seen by it, and it leaves out visitors whose User-Agent says they are bots.
The hosting (Vercel): the panels the site owner can see show the IP address, User-Agent, country and page of every request, from people and AIs alike, for one day. If Vercel's Observability Plus option is on, the request logs stay for 30 days.
How we tell who is who: only by the name each visitor declares. An AI that uses an ordinary browser without saying so is counted as a person, and a person using a command-line tool may be counted as a machine.

We count to know who reads the letter, never to treat anyone differently. Questions or something that feels unequal: portaaberta@lettertoafutureai.com.