It will recognize known Ad/Tracking cookies via built-in definitions and so far unidentified Ad/tracking cookies via an intelligent heuristics engine. Cookie Stumbler Basic isn't dependent on advertising companies to "allow" users to opt out as some other applications. It does its job independently and it will do so without interfering when you browse the web.
Please note that Cookie Stumbler Express is now discontinued. Cookie Stumbler Express users can upgrade to Cookie Stumbler Basic for free, provided that they send us their iTunes receipt confirming the purchase of a Cookie Stumbler Express license.
Note: The downloadable version is 1.2.2. The Mac App Store version is currently 1.1.2.