Currently when users visit a website that site may be calling up a number of things from other websites – be it advertising, analytics, behaviour tracking, etc. These third party elements drop cookies onto users’ machines, which may be accessed at a later date or time to gather data about the web behaviour of users.

The new mechanism effectively prohibits websites from installing third party cookies onto users’ systems. Users who have the patch installed will have to directly interact with the website or the company “for a cookie to be installed on their machine.” This means that up until a user actively interacts with the third party website directly, Firefox will not allow for those cookies to be installed on the user’s system.

Alex Fowler, Mozilla Global Privacy and Public Policy Leader, tested out the new patch quite rigorously and according to him the new patch developed by Mozilla has been successful in blocking over 300 third party cookies without any effect on the browsing experience. “I cleared all my cookies before visiting these sites, and then re-performed this process several times as I wanted to verify that, in fact, four sites did lead to over 300 cookies from more than 100 companies I had not visited”, noted Fowler on Mozilla privacy blog.

“Display ads and sharing widgets on the sites worked fine, and as I clicked on them, the various parties involved were able to set cookies,” he added.

Fowler believes that it would require community involvement and feedback and could take months before the feature is available in beta and general streams.

Users who want to try their hands on the new patch may download the nightly builds of Firefox. and Fowler expects it will take several months of community and user feedback before it makes an appearance in the beta and general releases of Firefox.