Cookies and Trackers, Explained

"Cookies" and "trackers" get thrown around constantly without much explanation of what they actually are. Here's the plain version.

What a cookie is

A cookie is a small piece of text a site stores in your browser. Your browser sends it back to that same site on every later request, which is how a site remembers you're logged in, what's in your cart, or a preference you picked earlier. On its own, a cookie is just a basic memory mechanism the web was built with.

First-party vs third-party

A first-party cookie is set by the site you're actually on, directly, and it's usually the harmless kind: it keeps you logged in on that one site.

A third-party cookie is set by a different domain embedded in the page you're visiting, like an ad network or an analytics script loaded alongside the site's own content. Because that same third-party script often gets embedded on many other unrelated sites too, it can recognize the same cookie on each one and piece together a picture of where you've been across all of them. That's what "tracking" means in practice: not one site watching you, but one company watching you across many.

What analytics scripts actually do

A typical analytics script runs quietly in the page, records things like which pages you viewed, how long you stayed, and what you clicked, and sends that data back to the company's own server. This is exactly the kind of request the local-only guide talks about: it's a common, easy way for a project to quietly stop being local without anyone deciding to add tracking on purpose.

Checking what a site is doing

Open your browser's developer tools, switch to the Network tab, and reload the page. Every request the page makes shows up there, including its destination. Requests going to a domain that isn't the one you're visiting are worth a second look; that's usually an ad network, an analytics service, or some other third party.

This site

ydnim.com runs none of this: no analytics, no third-party cookies, nothing tracking you across other sites. The privacy policy spells out exactly what little does apply.