Private Browsing is one of the new feature in Firefox 3.5 browser. Sometimes you do not want other users of your computer to see or access previously visited or the username and password information.
In a Private Browsing session, Firefox won’t keep any browser history, search history, download history, web form history, cookies, or temporary internet files. However, files you download and bookmarks you make will be kept.
To start Private Browsing
Select Tools > Start Private Browsing.
Note: When you start private browsing in firefox, it will save your current opened tabs and open it when you are done with your private browsing session.
To stop Private Browsing
Select Tools > Stop Private Browsing, or close Firefox.
What Private Browsing will not retain
Form and Search Bar entries
Download List entries
Web cache files
Start Firefox in a private browsing session
If you want automatically enable Private Browsing mode whenever you start Firefox, follow the steps below.
1. Select Tools
2. Select Options
3. Select Privacy panel tab.
4. Select Use custom settings for history in the Firefox will: select box
5. Check the box Automatically start Firefox in a private browsing session.
Also Read: How to enable Private Browsing in Apple Safari Browser.