The Google-Extended token in robots.txt decides whether already downloaded content may train future Gemini models and be used for grounding. It does not affect inclusion in Search or a ranking signal, and it has no User-Agent of its own.
What Yandex Direct and Google Ads say about geo delivery when the point changes, and why a VPN does not stop linking visits by a browser fingerprint.
Who identifies themselves in Metrica, how to verify Google and Yandex by DNS, how Google-Extended differs from Search, and why a failed check is not proof of a spoof.
What an autonomous system number says about routing, how a shared IPv4 under CGN differs from a person, and how a DNS address list is built.
Status 429 means too many requests and does not define who the user is. How a rate limit differs from a captcha, an IP block, and a single weak signal.
How JA4 folds a ClientHello into a string, how that differs from a browser fingerprint, and why the string alone does not prove an automated visit.
How a site recognizes a browser without a form. What the User-Agent header carries, what a fingerprint means, and how passive collection differs from active collection.
What Metrica does when JavaScript and Referer are both missing, how active collection in the browser differs from a request header, and why the absence of a script cannot be the only refusal.
What the HTTP User-Agent header says about the program, why browsers trim it, how Google asks you to verify a robot by something other than the string, and why one header is not enough to decide a visit.
An ASN is the number of an autonomous system with one routing policy, not a data-center label. Known data-center traffic appears in GIVT examples, and a Yandex address in Yandex’s own AS does not by itself prove a robot.
A W3C note calls a fingerprint the ability to recognize a browser by its settings and observable traits. Clearing cookies and using a VPN do not end that link, and article 11 of the statute does not call technical traits biometrics.
A forward proxy requests a site on the client’s behalf and does not always hide the address. MDN, the RFC, and Google Ads never define the phrase “residential proxy”.
How a Yandex Metrica robot differs from SIVT, a windowless browser, a search crawler, and a visit triggered by a chat question. A way to keep those cases apart.
A captcha in Yandex Direct and in the OWASP catalog slows automation, but the test can be solved. How that differs from a browser proof-of-work task.
In public descriptions a click bot is a program that imitates an ordinary browse for a click or an impression. How that differs from a windowless browser, a botnet, and repeated human clicks.
In the MRC standard a click farm is organized non-robotic activity through many people or machines. How SIVT differs from routine GIVT, and why a solved captcha does not prove a person.