Privacy Badger is an interesting browser plug-in made by EFF in order to help users prevent themselves from being tracked by advertisers and other online organizations.
Privacy Badger’s approach to the problem is interesting. Instead on being based on a white-list of good, non-tracking sites or a black-list of bad sites, privacy badger tries to take an algorithmic path to detect and block domains that engage in tracking.
Privacy Badger works by monitoring the behavior of 3rd-party domains that have content embedded across many sites, and detecting which ones try to implant tracking cookies. When such domains are detected, content from them is blocked to prevent further tracking.
The cookie-based approach isn’t perfect. The developers themselves admit that as it stands, privacy badger will not be effective against Browser fingerprinting. Still, it makes for an interesting effort in this crucial area.