Many third-party trackers exist on web pages across the Internet. These trackers are often advertisers, who set third-party cookies in your browser to track you anonymously as you browse the web. These trackers can track you across any web pages on which they are embedded. (For more information on third-party tracking, see the FAQ). Recent efforts (such as Do Not Track) aim to allow users to opt out of tracking of this type, and many tools (such as Ghostery) exist to help users understand and block third-party trackers. An easy way to address this type of tracking is to block third-party cookies, an option that is built into all browsers.
ShareMeNot targets a different type of tracking: the tracking done by websites with which you have an account, such as Facebook or Google. These trackers allow other websites to embed buttons (such as the Facebook “Like” button or the Google “+1” button) that you can use to share the current website with your profile on that site.
These buttons are found on many sites across the web. Whenever you see one of these buttons, the tracker (e.g., Facebook or Google) that provides it knows that you are visiting the current site, even if you don’t click the button and in some browsers even if you have third-party cookies disabled. This tracking does not happen anonymously if you are logged in to (or in some cases have ever been logged in to) the tracker’s site, since that tracker knows which account you’re logged in with. This tracking is possible because of how browsers work: your cookies as well as the address of site you’re viewing are sent to the tracker whenever one of these buttons is loaded. Disabling third-party cookies prevents this kind of tracking in Firefox (but not in Chrome), but prevents the buttons from functioning correctly.
Have your cake and eat it too
ShareMeNot is designed to prevent these sites from receiving any information about you until you actually click on the button, while still allowing you to use the button normally if you so choose. Rather than completely blocking the buttons and removing them from the web experience, ShareMeNot prevents the provider of a button (e.g., Facebook) from knowing who you are. ShareMeNot does this either by completely replacing the buttons with local stand-in buttons, making no requests to the trackers at all, or optionally by simply removing cookies from request made while real buttons are loaded. When you choose to click on a button, ShareMeNot necessarily allows the button provider to identify you so that the button can work as it normally would.