Cookies, Trackers, and Your Data: A Simple Explanation (2025)

NOTE

Websites leave crumbs (cookies) and invisible footprints (trackers) to learn about you. Below you’ll find a bakery tour—plus tips to keep the crumbs to yourself.

Every time you read the news, shop for shoes, or check the weather, sites quietly drop cookies—tiny text files that remember preferences, cart items, and sometimes your entire browsing history. Add third-party trackers (scripts from advertising companies) and your clicks can be stitched into a detailed profile.

This guide breaks down what these technologies do in everyday language and shows you beginner-friendly controls to limit snooping without breaking the web.

Table of Contents
1. Cookies: The Good, the Bad, and the Crumbly
2. Trackers: Cookies’ Invisible Cousins
3. How to See Who’s Watching
4. Quick Fixes to Limit Tracking
5. Common Pitfalls
6. Troubleshooting
7. Going Further
8. Conclusion

1. Cookies: The Good, the Bad, and the Crumbly

Type	Example Use	Privacy Risk
First-party cookie	Remembering dark mode setting	Low
Session cookie	Staying logged in to email	Low
Third-party cookie	Tracking ads across websites	High

Cookies are small text snippets your browser stores. The key difference is who sets them:

First-party: Created by the site you’re visiting (e.g., nyt.com). Useful for convenience features.
Third-party: Planted by domains you’ve never heard of (doubleclick.net). These follow you across multiple sites to serve personalised ads.

2. Trackers: Cookies’ Invisible Cousins

Even if you block cookies, sites can load JavaScript from ad networks that fingerprint your device: screen size, fonts, battery level, and more. These data points form a near-unique ID.

Common tracker types:

Pixel tags – 1×1 images (similar to email tracking pixels).
Fingerprint scripts – collect hardware details.
Social widgets – like buttons that phone home to Facebook/Twitter.

3. How to See Who’s Watching

Browser Dev Tools → Network tab → filter by third-party domains.
Install Lightbeam (Firefox add-on) to visualise connections.
Visit https://whotracks.me for a tracker database.

TIP

In Chrome, click the padlock icon → Cookies to list all cookies for the current site.

4. Quick Fixes to Limit Tracking

Action	Difficulty	Effectiveness
Block third-party cookies	⭐	High
Use browser’s Tracking Protection	⭐⭐	High
Clear cookies on browser close	⭐	Medium
Install a content blocker (uBlock)	⭐⭐	Very High

A. Block Third-Party Cookies

Chrome → Settings → Privacy & Security → Cookies → Block third-party cookies.
Firefox (strict mode) does this by default.

B. Enable Built-In Tracker Blocking

Safari: Prevent cross-site tracking is on by default.
Edge: Settings → Privacy → choose Strict.

C. Auto-Delete Cookies

Add Cookie AutoDelete (Firefox/Chrome) to wipe cookies minutes after you leave a site.

5. Common Pitfalls

Mistake	Consequence
Deleting all cookies	You’ll be logged out everywhere
Whitelisting every site quickly	Trackers sneak back in
Over-blocking essential scripts	Pages may break (captchas fail)

6. Troubleshooting

Issue	Fix
Shopping cart empties itself	Allow first-party cookies for that store
Videos won’t play	Disable blocker temporarily or add site to exceptions
Sites still show “cookie pop-up”	Use I Don’t Care About Cookies extension

7. Going Further

Try privacy-oriented browsers like Brave or Tor for stronger defaults.
Use DNS-level blocking (NextDNS, Pi-hole) to filter trackers across devices.
Read our guide on browser fingerprinting to understand advanced tracking.

8. Conclusion

Cookies and trackers aren’t inherently evil—some keep your online life convenient—but third-party variants often overreach. By blocking cross-site cookies, enabling built-in protections, and using a trusted content blocker, you regain control without needing deep tech skills. Start small: toggle one setting, browse, and expand as you get comfortable.

Happy crumb-free surfing! 🍪🚫

Table of Contents