Mozilla is out today with the new Firefox 20 open source web browser release. The new browser is notable in that it provides a privacy fix that some users have been asking about for over four years.
The Firefox 3.1 release back in 2008, introduced a Private Mode for browsing. In private mode, user history and cookie information is not retained after the browser is closed. Since 2008, there has been a bug listed against Private mode, that the Firefox 20 release finally fixes.