How Websites Track You

Understanding the technologies and techniques websites use to monitor your online behavior.

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Website Tracking Methods

Every website you visit collects data about you. Most tracking is invisible, happening in the background to build profiles for advertising, analytics, and personalization.

Main Tracking Technologies

Cookies

Small text files stored on your device. Track sessions, preferences, login status. Can follow you across sites.

Tracking Pixels

Invisible 1x1 images. Load when you view page or email. Report back to server with your info.

Browser Fingerprinting

Identify you by unique browser configuration. Screen size, fonts, plugins create unique signature.

Local Storage

Similar to cookies but stores more data. Persists even after clearing cookies. HTML5 feature.

JavaScript Tracking

Scripts collect mouse movements, scrolling, clicks. Heatmaps show exactly how you interact.

Social Media Plugins

Facebook Like, Twitter Share buttons. Track you even if you don't click. Report to social networks.

What Websites Track

  • Pages Visited: Full browsing path through site. Time spent on each page.
  • Referring Site: Where you came from. Search terms used to find site.
  • Device Info: OS, browser, screen size, language, timezone.
  • Location: IP address reveals city/region. GPS if permission granted.
  • Click Behavior: What you click, hover over, ignore. Scroll depth.
  • Form Interactions: Which fields you fill. Even abandoned forms tracked.
  • Mouse Movements: Heat maps of cursor path. Session recordings.
  • Purchase Intent: Items viewed, added to cart, purchased.

Third-Party Trackers

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Google Analytics

Used on 86% of websites. Tracks detailed behavior. Builds profile across all sites using it.

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Facebook Pixel

Tracks visitors for Facebook ads. Follows you even without Facebook account. Retargeting tool.

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Ad Networks

Google Ads, DoubleClick, others. Track across thousands of sites. Build comprehensive profiles.

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CDNs

Cloudflare, Akamai serve content. See traffic to millions of sites. Potential for tracking.

Cross-Site Tracking

Third-party cookies allow tracking across different websites. Ad networks see your activity on all sites using their ads. This builds comprehensive browsing profiles:

  • Visit camping site → see camping gear ads everywhere
  • Research medical condition → see related ads for weeks
  • Shop for engagement ring → ads follow you, spoiling surprise
  • Browse political content → profiled for targeted messaging

Fingerprinting Explained

Canvas Fingerprinting

Draws hidden image using your graphics card. Slight differences between systems create unique ID.

Font Fingerprinting

Checks which fonts installed. Combination of fonts unique to your system.

Audio Fingerprinting

Plays silent audio. Hardware differences create unique audio signature.

Battery Status

Checks battery level and charging status. Surprisingly identifying data point.

Blocking Tracking

Browser Extensions

uBlock Origin: Blocks ads and trackers. Open-source. Highly effective.
Privacy Badger: EFF tool. Learns trackers as you browse.
Ghostery: Shows and blocks trackers. Educational interface.

Privacy Browsers

Firefox: Enhanced Tracking Protection. Privacy-focused mission.
Brave: Built-in ad/tracker blocking. Privacy by default.
Tor: Maximum anonymity. Slow but very private.

Browser Settings

Block third-party cookies. Enable Do Not Track. Clear cookies on exit. Disable fingerprinting.

Cookie Types

  • First-Party Cookies: Set by site you're visiting. Store login, preferences. Generally necessary.
  • Third-Party Cookies: Set by other domains. Advertisers, analytics. Track across sites. Block these.
  • Session Cookies: Deleted when browser closed. Temporary.
  • Persistent Cookies: Stay until expiration date. Can track over long periods.
  • Zombie Cookies: Recreate themselves after deletion. Flash cookies, ETags. Sneaky.

Email Tracking

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Tracking Pixels in Email

Invisible images report when you open email. Track device, location, time. Disable image loading.

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Link Tracking

Links redirect through tracking servers. Know which links clicked. Use plain text email.

Protecting Against Tracking

Use VPN

Hides IP address. Makes location tracking harder. Encrypts traffic from ISP snooping.

Clear Cookies Regularly

Delete on browser exit. Breaks tracking chains. Use private/incognito mode.

Use Container Tabs

Firefox Multi-Account Containers. Isolate Facebook, shopping, etc. Prevents cross-site tracking.

Privacy Search Engine

DuckDuckGo, Startpage. Don't track searches. No personalized results bubble.

DNS-Level Blocking

Pi-hole, NextDNS. Block trackers network-wide. Affects all devices on network.

Disable JavaScript

NoScript extension. Blocks tracking scripts. Breaks many sites. Use selectively.

Check Your Tracking Exposure

  • Panopticlick (EFF): Test your browser fingerprint uniqueness
  • Cover Your Tracks: See what trackers detect about you
  • Browser Leak Test: Check for IP, DNS, WebRTC leaks
  • Am I Unique: Comprehensive fingerprinting test