Tracking protection is still hard to measure
accurately, because there are many different
kinds. The Aloodo project can pick up everything,
including lesser-known vintage tools such as AVG
and even behavior-based tools like Privacy
Badger that take
a while to get
trained and start blocking.
The biggest protection tools are the browser
built-ins. Apple Safari has had Intelligent Tracking
Prevention, and Mozilla Firefox is testing Enhanced
Tracking Protection. We have added a quick test that
should cover both of these. Now there is an
onBlocked callback to take action when we can detect
right away that a user has this form of protection
because a third-party cookie won't persist.