Lesson 1 of 5
What is a tracker?
From pixels to SDKs.
4 min read
A tracker is any resource whose purpose is to record information about you. The classic examples are 1×1 pixel images and JavaScript snippets like Google Analytics or the Meta Pixel.
Modern trackers chain together: one script loads another, which sets a cookie, which feeds an ad auction. A typical news article includes dozens of them.
Key takeaways
- Trackers can be visible (Like buttons) or invisible (pixels).
- Most pages load 20-50 third-party trackers.
- Blocking the first tracker often blocks the rest of the chain.