Priv3+ removes cookies from all third party requests, such as requests for social widgets, and small gifs or invisible iframes for behavioral advertising. This approach prevents third parties from tracking you using cookies. As a result, social networks such as Facebook and Twitter cannot track whichever web page you visit: they should not know every page you view that embeds a social widget, just because you are logged in on their website!
Priv3+, however, enables you to enjoy social networking features whenever you want them: when you interact with the social widget, Priv3+ loads the third-party element, this time with cookies: The first click selectively reloads the element, and the second click performs the regular action. The selective reload does not load any other items and does not cause a whole-page refresh unlike other addons (e.g., Ghostery).
Say you are logged in to Facebook in another tab or window. You visit a page with a Like button. You will see how many people liked that page, but Facebook will not be able to tell whether you visited that page, because your cookies were not sent to Facebook when the button was loaded. If you click once, the button will be reloaded with cookies, and Facebook will show you how many of your friends liked that page. If you want to like the page, you can do so with the second click.
The additional benefit of this interaction-based cookie behavior is that behavioral advertising companies cannot track you via cookies: Small gifs and invisible iframes from these third parties are embedded on a page, so that they can receive the cookies they may have set to you when you were visiting other websites, tracking you across websites. Priv3+ removes these cookies when these 'invisible' elements are loaded. If you cannot see them, you cannot interact with them! That means, these third parties will never receive their cookies, preventing them to track you across websites!
And all this happens without any blacklist! When there is no blacklist to maintain, there is no chance to miss any third party tracker. Priv3+ will not update anything related to tracker lists, because it does not use/need/require one.
If you want, you can add the third parties you want to your whitelist, either for a certain website or all of them. It is totally up to you. In other words, only you have control over when third parties learn your visits to web pages!
Note that Priv3+ does not delete any cookies that exist in your browser nor does it prevent third parties to set cookies. Priv3+ only enables sending these third party cookies *when* and *if* you interact with the third party content. If not, the third parties never receive the cookies and cannot track you using them. Otherwise, Priv3+ does not in any way interfere with your cookies.