For the moment there is no obvious way to prevent companies using these sorts of technologies from collecting a fingerprint from your computer. So what can you do to protect your privacy from adverting networks and other organizations that may wish track your activities on the Internet?

Do not track (DNT)

You can tell Web sites that you do not wish to be tracked by setting your browser to use the Do Not Track (DNT) header, which is communicated to every Websites you visit. You can set the Do Not Track header in the latest versions of Firefox and Internet Explorer and Safari, although Chrome does not support it at all.

Unfortunately honoring your DNT preference is entirely voluntary, and many organizations choose to ignore it. (That shouldn't be surprising: supercookies have been expressly designed to ignore users preferences by respawning cookies when they have been deliberately deleted.)


However, Elise Dietrich, a privacy and data security legal expert at Washington based law firm Sullivan & Worcester, believes that honoring DNT could soon be made the law.

"There are some bills pending, although at the moment they are a little light on technical specifics," she said. "Ultimately, what will be important is whether consumers have to opt in or opt out of tracking, and under current U.S. law opt-out is the norm. But, either way, I definitely think we will see some legislation in the next year or two."

In the mean time, here's a few things you can do now to protect your privacy:

Opt-out - You can use the Network Advertising Initiative (NAI) online Opt-Out Tool to replace cookies placed by some advertising networks on your computer with an Opt-out cookie, which can prevent them from sending tailored advertisements to your browser, although they may still track you. Google offers a plug-in for Chrome called Keep My Opt-Outs that allows you to prevent your Opt-out cookies being deleted when you delete all the other cookies in your browser.

Disable third party cookies in your browser - This can be done with a few mouse clicks in most browsers. Disabling third party cookies will help to reduce the number of sites that track you using conventional browser cookies, but not ones that store cookie information in Flash local shared object storage

Disable Flash cookies - you can disable and delete them directly using the Adobe's online control panel or by right clicking on Flash content displayed on a Web page, choosing settings, and then selecting the options you want in the Storage tab. Internet Explorer 8 should delete them along with standard third party cookies -- if you have Flash version 10.3 or higher on your machine.

Clear your browser cache - Although KISSmetrics has stopped using ETags to track website users, there's no guarantee that other companies won't adopt the technique. To defeat them, clear your browser cache after each Web site you visit

Disable JavaScript scripting – Disabling Javascript in your browser makes it much harder for organizations to track you using ETags or Flash cookies, but it may make some sites unusable.

Some useful privacy tools

CCleaner (Windows) registry cleaner tool which also removes Flash cookies.

FlusApp (MacOS) tool for reviewing and removing Flash cookies.

Betterprivacy (Firefox) add-on offering selective Flash cookie blocking.

TrackerBlock (Firefox) add-on offers selective cookie blocking, control over Flash and HTML5 cookies and the ability to prevent Opt-Out cookies from being deleted.

Ghostery (Firefox, Chrome, Safari, Opera and Internet Explorer) browser tool for shows you which companies are tracking you on any given webpage, and also provides the option to remove Flash and Silverlight cookies when you exit your browser.

NoScript allows blocking JavaScript from most sites, while allowing you to whitelist trusted sites.

Collusion (Firefox) add-on builds up a graph of all the organizations that track you, and how they are connected, while you browse.

Paul Rubens has been covering IT security for over 20 years. In that time he has written for leading UK and international publications including The Economist, The Times, Financial Times, the BBC, Computing and ServerWatch.