I gotta tell ya about this other Firefox plugin. Yesterday I signed some Mozilla-sponsored petition. After coming here and reading one of ka9yhd's posts on Firefox using a lot of memory, I looked at tasks running. There was a persistent cookie from that Mozilla petition site. And it had spawned another 4 tasks for a total of 5, each consuming some 2.5 MB of RAM. (I'm guessing a new task was spawned each time I visited a new site.) I dumped all my web cookies. Had to sign back in here as a result. But, that tracking cookie's 5 tasks were still running in memory, even though it did not show in the Firefox list. It persisted until I closed Firefox.
While looking at Tor addons today, I came across the
Self-Destructing Cookie addon. Briefly,
Self-Destructing Cookies is not just a cookie manager, it's a new cookie policy. ... Self-Destructing Cookies automatically removes cookies when they are no longer used by open browser tabs. ... Tracking cookies will be detected and removed immediately. They are identified purely by their behaviour - no need for a blacklist that needs to be kept up to-date.
So far, it is working as advertised. As I said before, I dump all cookies after closing a web browsing session, anyway. This addon dumps a site's tracking cookies automatically within 10 seconds of leaving the site. Of course, the preferences are adjustable.