1. shabbirh
Purge Your Private Data
Firefox records where you've been browsing to help you retrace your steps, as well as to reopen the pages you've visited previously more quickly. But this feature may compromise your privacy by letting other people using your PC see what you've been up to.
The browser's default security settings may not strike the balance of convenience and privacy that's best for you. To customize those settings, select Tools, Options, and click the Privacy icon. The dialog box is divided into three sections: History, Cookies, and Private Data.
History: You might want to shorten the number of days Firefox saves your surfing history--the default is nine days. If you don't want to save your browsing history at all, uncheck Remember visited pages for the last [X] days (see the full screen of the thumbnail). You can also choose not to record the text you enter in Web forms or search boxes, and the programs you download.
cookie: A cookie is merely a small file that a Web site puts on your PC to identify you, or to store information about you or your computer, such as your IP address. The good ones save you the trouble of logging on to the site on return visits, a big help if you use subscription news services such as that of the New York Times.
The bad cookies are placed by ad companies that pay for the right to place advertising on the sites' pages (some sites also leave their own ad cookies). These files track your visits to pages that display their clients' ads (or their own), and they may tailor the ads you see to your browsing history.
Over time, cookies can reveal your browsing habits, though standard ad cookies, like those that DoubleClick uses, can't attach a name to a specific surfing trail.
That means, if you wipe out your cookies as soon as you close your browser, the ad networks never get a chance to track your surfing from session to session.
Firefox 2 can accept, and regularly wipe away, any cookie you haven't explicitly told it to keep: Click Tools, Options, Privacy, check Accept cookies from sites, and in the 'Keep until' drop-down box, select I close Firefox. To keep cookies from a few trusted sites, click Exceptions, and in the dialog box, enter the URLs of the sites whose first-party cookies you wish to keep in the 'Address of web site' field. Click Allow for each, and when you're done, click Close And OK. If you're using Firefox 1.5, click Tools, Options, Privacy, Cookies, check Allow sites to set cookies, and choose for the originating site only.
Private Data: To clean things out regularly, check Always clear my private data when I close Firefox. Then click the Settings button to fine-tune the options.
What should you leave checked and unchecked in the Clear Private Data dialog box? Checking the 'Browsing History' and 'Cookies' sections will override any changes you made in the other sections of this dialog box, so leave them unchecked. Checking 'Cache' may slow Firefox down a bit, but probably not enough for you to notice if you have a fast Internet connection. Deleting 'Saved Passwords' is entirely pointless. You should check every other option. After you click OK to close the Clear Private Data dialog box, uncheck Ask me before clearing private data to avoid this annoying pop-up dialog box.