I some cases it can really work.

In most cases, the add-ons will conflict with each other and not allow them to do their job.

I suggest only using one.

NOTE: I believe that Ghostry is only to see what is tracking you. Unless it has changed, I don't think that it stops site from tracking you.

Hello Omar_Otmane

confirm ComputerWhiz reply : In most cases, the add-ons will conflict with each other and not allow them to do their job.

also maybe you have lag and slowness in your browsing

try one with the most positive reviews !

thank you

Note that you usually do not need to enable third-party cookies and that current Firefox version have a setting to allow third-party cookies from visited sites.
So if you have never visited the web page then such third-part (tracking) cookies won't get set.

• https://support.mozilla.org/kb/Disabling+third+party+cookies