After disappearing for a long period of time thanks to changes in requirements for Safari plugins, the fine folks at DuckDuckGo have revised and refreshed their Privacy Essentials plugin. This plugin does two very cool things:
First, it gives each site you visit a rating related to the privacy controls, trackers and other technical details of the site itself.
Second, it offers the ability to block trackers directly from within the plugin. But even cooler, it tells you the difference in the privacy ating it would have given with and without the blocking.
This is available in the Mac App Store now: