Mozilla has released a public preview of the Firefox 3.1 Beta 2, which includes new features as well as improvements to performance, web compatibility, and speed.

This Beta version, which is intended for developer testing and community feedback, is now available for download.

New features and changes include availability in 54 languages, as well as a new "Private Browsing Mode" that allows you to browse without Firefox storing any traces of where you?ve been.

While you browse the web, your browser usually records a lot of data which will later be used to improve your browsing experience. For example, it records a history of all the web pages you have visited, so that later if you need help remembering a site you visited a while back, it can assist you in finding that site. But hose data can be used to trace your online activities. For example, if your coworker sits at your computer, she can view all of your browsing history, which may not be what you want.

One option would be to do your work, and then clear the data that Firefox has stored for you, such as history, cookies, cache, .... But the problem is that this action will also remove the parts of your online activities data which you don't want to hide, so the history that Firefox records can no longer be used to find a web site you had visited a month before. Private Browsing will help you here.

Private Browsing aims to help you make sure that your web browsing activities don't leave any trace on your own computer. Note that Private Browsing is not a tool to keep you anonymous from websites or your ISP, or for example protect you from all kinds of spyware applications which use sophisticated techniques to intercept your online traffic. Private Browsing is only about making sure that Firefox doesn't store any data which can be used to trace your online activities, no more, no less.

Private Browsing mode will be available from the Tools menu of the FireFox browser.

Other features of the Firefox 3.1 Beta 2 include support for web worker threads and that a new TraceMonkey JavaScript engine is now on by default for web content.

Mozilla has also made improvements to the Gecko layout engine, including speculative parsing for faster content rendering and removed the new tab-switching & preview behavior based on feedback from Beta 1 users

Firefox 3.1 Beta 2 also offers support for new web technologies such as the