It’s not just your base browser that can betray you online and pass along your private information. One of the leading threats to anonymity are optional plugins, which bypass the traditional page paradigm to communicate directly with their creators. They even store identifying files on your computer without your knowledge. Normal browsers use files called “cookies” to do this, but you have the option to disable them. These plugin-generated “supercookies,” though, are harder to deal with. Thankfully, utilities like SlimCleaner and plugins like BetterPrivacy allow you to purge them and block new ones from being created.