According to Web metrics company , of all browsers used during November, marking the first time that the open-source browser broke the 20% barrier for an entire month.

Few users are trying Firefox 3.1, however; last month, only 0.05% of all users were running a preview of the new version, Net Applications said.

There will be at least . Two weeks ago, Mozilla said it had added a third beta to the process, in part to evaluate some of the features introduced Monday, including TraceMonkey and Private Browsing, and to allow time for programmers to fix the bugs that users report.

Firefox 3.1 Beta 2 for Windows, Mac OS X and Linux from Mozilla's site. Users already running Beta 1 will be notified of the available update in the next 48 hours.