How does the Private Browsing mode work in Firefox 3.5?
Suppose you’re shopping for a surprise gift, so you don’t want the sites you’ve been viewing stored in your browser’s history. You can enter private browsing mode by going to Tools->Start Private Browsing. A simple dialog screen confirms you’ve entered this mode and nothing you encounter on the Web will be recorded from that moment on: none of the websites you visit and none of the cookies you collect will be saved. Exit private browsing mode through the Tools menu again and you’re back to normal browsing.