Have little boxes begun popping up on your web pages? They showed your picture and welcomed you by name. They also included details that make it clear these sites know you are a Facebook member. You probably shouldn’t be surprised. Other sites have used cross-site cookies to determine the ads they display. If this is enough to spur you into action, it might be time to get rid of all your web browser cookies.

But what are the consequences of deleting cookies? They are, after all, intended to make surfing easier. They give your computer a unique identifier so your actions can be tracked and your needs (say, your site login information or preferences) anticipated. We thought it would be an interesting experiment to delete all our cookies and see what happened as a result.

Removal process
You delete cookies by taking a trip to your browser’s preferences. In Apple’s Safari 5, choose Safari > Preferences, select Security, click Show Cookies, and finally click Remove All. With Mozilla Firefox 3.6.8, select Firefox > Preferences and click on Privacy. Select the Remove Individual Cookies link and then click
Remove All Cookies.

Safari’s Security preferences give several options for dealing with
cookies. We use the third choice – to only accept cookies from sites we visit

Losing your login
Once you get rid of your cookies, the first thing you’ll notice is that you won’t be logged in to sites you visit regularly. Amazon asked us to “sign in to get personalised recommendations”. A forum we visit regularly took us straight to a Login page. When we went to our own website’s administration page, we were prompted to log in there as well. This shouldn’t be a hassle if you’ve been storing usernames and passwords in Safari’s AutoFill preferences, for example. (Go to Safari > Preferences, click AutoFill, and then select the User Names And Passwords option.) If you have, then Safari will enter your usernames. Passwords stored in your keychain will be filled in as well.

One thing you won’t notice is changes due to the loss of the cookies advertisers use to track your activity on the web. These cookies don’t require you to log in anywhere – they just record what you do. Deleting these is a good way to keep your surfing habits private; but as you surf, you’ll get new cookies, and, over time, the ads you see will be, once again, somewhat influenced by your browsing history. It didn’t take long after we got rid of our cookies before our browser showed hundreds of new cookies in its list. A half dozen per site is common.

A regular clear-out
While you could go as far as turning off cookies in your browser, this can prevent certain websites from working correctly. For example, you can’t buy anything on Amazon.co.uk or log into Facebook if you do so.

Instead, we would settle for deleting cookies regularly. Several tools can help, including Intego’s $20 [£12] Washing Machine 2 (www.intego.com), which can also delete browser caches and other dross either on demand or on schedule. Titanium Software’s free Onyx (www.titanium.free.fr) can clean cookies from a couple dozen browsers, though you can’t schedule it to run automatically. Deleting your cookies from time to time can clear out the hundreds or even thousands of them that accumulate. And in the process of doing this, it will give you a new pristine identity when you visit websites where you don’t have to log in.