Firefox increasing rate since Firefox 1.0 was released on November 9, 2004, and Firefox had already been downloaded over one billion times. This number does not include downloads using software updates or those from third-party websites. They do not represent a user count, as one download may be installed on many machines, one person may download the software multiple times, or the software may be obtained from a third-party. In July 2010, IBM asked all employees (about 400,000) to use Firefox as their default browser. Firefox was the second-most used web browser until November 2011, when Google Chrome surpassed it. According
Internet Explorer 9 Chrome and Internet Explorer." The release candidate was also "perfectly" compatible with far more sites than the beta, but there are still issues with some sites because their developers are not yet testing with the new browser. The RC scores 4 out of 5 ("very good") for now. On its first day of commercial availability, Internet Explorer 9 was downloaded over 2.35 million times. Blogging his March 2011 performance tests for ZDNet, Adrian Kingsley-Hughes concluded that Chrome 10, Internet Explorer 9 (32-bit) Final Release, Opera 11.01 and Firefox 4's Release candidate were "pretty evenly matched... Microsoft has worked hard on