I have dealt with Firefox security add-ons about a month ago and promised to write another guide this time dealing with privacy related add-ons. So what’s the core difference between privacy and security anyway? I personally consider privacy to be a part of security, which explains for instance why Ghacks has only a security category, and no privacy category.
Privacy is about user information. This can be data like names, addresses, emails but also indirect data like a user’s browsing habits, past purchases at an online store or a search history. Companies use the information for instance to track a user on the Internet to display targeted advertisements. But privacy can also be abused, say by malicious users who hacked into a company database to get all user names and emails, to communicate with those others afterwards (phishing comes to mind). Privacy can also be a local matter. A wife who does not want her husband to find out what she is doing on the Internet, parents who do not want their kids to see some of the sites they have been visiting.
Privacy add-ons cannot protect from all threats related to privacy. They cannot be used for example to delete your shopping history at Amazon or eBay. They can however protect you from the majority of dangers.
Firefox Privacy Preferences
Firefox has a few privacy related options that can be customized easily to improve privacy immediately. You find the settings by clicking on Tools > Options, or Firefox > Options in the menu. Switch to the privacy tab. The default setting here is to remember history. If you switch that to custom settings for history you get several new configuration options.

All of those settings are about local information, like the download or browsing history. If you do not want the browser to record the information, uncheck the box. You can also configure Firefox to clear the history on exit, which would mean that you have access to the history during sessions, but not after the browser gets closed down.
Helpful articles:
How To Clear A Browser Cache
How To Delete Cookies On A Computer
Configure Firefox To Delete All Cookies On Exit But Select Ones
Firefox Privacy Add-ons
Firefox offers many privacy related add-ons for download. This list includes only add-ons that are working under Firefox 4. The majority will work under Firefox 3 as well, I try to mention it if an add-on does not.
Create a temporary email address for immediate use on the Internet. Handy for signing up on websites that you do not trust to keep your email address confidential, or submitting a comment on a site.
Alternatives are Less Spam, please, Bloody Vikings and Spamadvert.
Forms

Firefox records by default what a user enters into forms on web pages. While it is possible to delete all form history at once via the clear browsing data tool, it is not comfortable to delete select form entries. You can visit the form again, enter the first characters of the text you have entered, hover over the suggestion that pops up with your mouse and press the delete key on your keyboard to delete it.
Form History Control simplifies the process. It displays all form data that is currently stored in the browser. You can use it to view, edit and delete entries easily.
Displays the form action on mouse over. The form action determines to which website or server the entered data is submitted to. This is sometimes used in malicious ways, for instance on phishing sites.
Tracking
An ad blocking extension that can be extended with subscriptions to include privacy related protections to the web browser.
Better Privacy
Protects a user’s privacy by offering better Flash Cookie (LSO) handling in Firefox. Can remove Flash cookies automatically on exit, something that will be supported by Firefox soon by default.
Protects against malicious cross-domain requests, including Cross-Site Request Forgery.
CsFire protects you against malicious cross-domain requests, by rendering them harmless. This means that CsFire will remove authentication information (cookies and authentication headers), which ensures that a cross-domain request can not have harmful or undesired side-effects.

Displays information about page elements used to track website visitors. This includes tracking pixels and scripts such as Google Analytics or Facebook.
A collection of tools that improve a user’s privacy on the web. This includes email and phone protection, blocking of online tracking, cookie controlling and privacy alerts that display trackers that are active on a site.
Delete cookies on-demand and based on pre-defined rules. You can use the add-on to clean up cookies from specific sites, or all cookies but those from some websites.
A similar extension is Cookie Whitelist.
Block companies from tracking you through cookies and Flash cookies. Blocks more than 300 different ad companies from tracking users on the Internet.
Uses random search queries to protect against search data profiling.
Misc privacy extensions
A boss key to minimize the browser immediately.
Displays certificate updates to give the user a tool at hand to verify the legitimacy of updated certificates.

Can be used to force HTTPS connections to select websites, for instance to always connect via HTTPS to your email provider, favorite websites or financial sites.
Informs the user if an https version of the website is available. Can create rules for HTTPS Everywhere.
Turns shortened urls into their destinations so that it is possible to see the link target right on the site the short url was posted on.
Validates Firefox HTTPS security errors by querying select Network Notaries.
A web proxy add-on for Firefox. Use proxy servers to hide your real IP address or visit websites that would be blocked otherwise.
Proxilla Glype Proxy Client is an alternative, as is Phzilla and Go2 Proxy
Closing Words
Firefox users can improve their privacy with add-ons tremendously. The right selection depends entirely on their web use. Do you think an add-on is missing from the list? Let everyone know in the comments. Post your privacy tips there as well.
Enjoyed the article?: Then sign-up for our free newsletter or RSS feed to kick off your day with the latest technology news and tips, or share the article with your friends and contacts on Facebook or Twitter.Related Articles:
Manage Flash Cookies with Better PrivacyPrivacy and Security Add-ons for Firefox 2.0
Privacy Extension for Firefox, Priv3
Square Privacy Cleaner, Clean Privacy Related Data In Windows
Protect your privacy from Google AdSense’s new behavioral ads

is it possible to stay inline annonymous so that f.eg. not Google, nor police can find out i was online or on specific sites? and would be nice if You Martin would explmain what ir proxy and how it works :)
You are missing RequestPolicy. IMO it’s one of must-have plugins. It allows to easly filter content from tracking sites, ad services and other unwanted sources.
How about ipflood? It’s not perfect but can make websites think that you’re on a proxy. -https://addons.mozilla.org/en-US/firefox/addon/ipflood/
Martin, A very useful list for everyone, I think Disconnect is also another very useful plugin for preventing search engines from tracking user actions.
URL – http://www.disconnect.me/
Hi all
I think that noscript lakes.
For cookies, cookies monster is a good add on about dealing of cookies
“Beef taco” is an opt-out cookie add on that substitutes an opt-out cookie for the site’s own.
One of your more extensive reads with who i have to complement you.
Naturally there are extensions/ add-ons missing and hopefully you will go on with suggesting with top quality material, like you did in the last two articles.
This is my personal computer at home. No one else has access to it. My privacy concerns are nicely met by a few free programs:
A good HOSTS file blocks those annoying animated ads:
http://www.mvps.org/winhelp2002/hosts.txt
Ccleaner has an option to keep necessary cookies for your banking, etc., while deleting the rest after your browser session. {Its main function is its registry cleaning which has won much praise.}
http://www.piriform.com/CCLEANER
For all around anti-virus protection Microsoft’s own Microsoft Security Essentials works well, doesn’t take over your computer, and is updated daily.
I disabled the User Account Control settings in the Control Panel since I find the messages annoying. Remember, the only vulnerable period on my personal computer is my time on the internet. I beefed up the Firefox 4 browser with ‘NoScript’ which so far has kept the bad guys away.
These are my personal choices. The rest of the histories of sites visited, etc, are not a concern since no one but me uses the machine.