Privacy › Module 1 › Lesson 2
How You're Tracked Online
Understand cookies, trackers, fingerprinting, and how sites follow you across the web
Opening
The web remembers more than you think
Ever searched for shoes and then saw shoe ads everywhere? That is tracking at work. Websites, advertisers, and data companies link your visits, devices, and interests into profiles used for ads, analytics, and sometimes resale. You cannot block every tracker, but understanding how tracking works helps you choose better tools and settings.
1. Cookies — Small Files With Big Memory
Cookies are text files stored by your browser. First-party cookies come from the site you visit—they may keep you logged in or remember cart items. Third-party cookies come from other domains embedded on the page, often ad networks. Modern browsers increasingly block third-party cookies by default, but trackers adapt with new methods.
2. Other Tracking Methods
Tracking pixels
Tiny invisible images in emails or web pages. When they load, the server records that you opened the message or visited the page.
Device fingerprinting
Combines browser version, screen size, fonts, and timezone to guess who you are without a cookie. Harder to clear than deleting cookies.
App SDKs and mobile IDs
Apps may send analytics and advertising IDs to multiple companies. Permissions like location and contacts widen the profile.
Login and social widgets
“Sign in with Google” or embedded Like buttons can share activity across sites when those services are present.
3. Who Uses This Data?
Advertisers target ads and measure campaigns. Analytics firms help sites understand traffic. Data brokers may buy or scrape information to build marketing lists. In security terms, more data in more places means more breach and misuse risk.
Check what your browser already blocks
Open your browser privacy settings and review blocked trackers, cookie rules, and “Do Not Track” or Global Privacy Control options. Combine browser settings with a reputable privacy extension only from official stores.
Knowledge Check
Third-party cookies are primarily associated with:
Multiple choice
Knowledge Check
Device fingerprinting tries to identify you using:
Multiple choice
Knowledge Check
True or False: Embedded social login buttons can contribute to cross-site tracking.
True or False