As Mozilla Firefox 3.5 released yesterday seems to be stable and speedy. Mozilla introduced private browsing in Firefox 3.5, which will not save any browsing history for that session however, bookmarks made and files downloaded in that session will be kept.
To start private browsing, open Firefox and from menu and select New Private Window
You can even start Firefox in private browsing whenever Firefox starts.
To start Firefox in a Private browsing session automatically whenever it starts
1. From menu click Options, select ‘Privacy’ tab
2. In History, chose Firefox will:”Use custom settings for history” and below that select ‘Always use private Browsing Mode’, when restart Firefox dialog appears, click ‘OK’ to apply the changes.
3. Now whenever you open Firefox, private browsing session will be opened.