Self Destructing Cookies Tutorial | Stop Online Tracking
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Tracking cookies are used to follow a user as they browse a website so that their behavior can be monitored. For example, let's say that advertiser.com is an ad service used by your favourite website, example-1.com. When you visit example-1.com it will show you an ad from the ad service. When this happens a cookie is put on your computer telling advertiser.com that you have been shown an ad X number of times, and have clicked it Y number of times on Z pages. Not a huge issue right? Well, what if your second favourite website, example-2.com, also used advertiser.com. The result of this would be that if you went to example-1.com and then to example-2.com, the ad service would know that you went to both sites, and would know which pages you went to on each of them. This can be an immensely powerful tracking tool, and this is only one example of their use. Luckily, there's an add-on to stop this.
Self Destructing Cookies
Self Destructing Cookies is a Firefox add-on that does exactly what the name implies: it destroys the cookies on your computer after you're done with them. The way that this works is that if you go to example-1.com and browse around, shortly after you close the tab (10 seconds by default), the cookies from example-1.com are destroyed. Thus, if you then go to example-2.com the advertiser wouldn't be able to tell that you were on both sites.
Of course, if you have some knowledge about cookies already you'll know that this can be stopped without any add-ons by simply setting your browser to not accept third party cookies. While I recommend that all users disable third party cookies, the reality is that there are still many cases when cookies can be used to track you. An example provided by the Self Destructing Cookies develop is browsing an online store. If you are browsing Amazon checking out the latest Justin Bieber album and are logged out of your account, Amazon will place a cookie on your computer to record that information. If you log into your account later, Amazon will see the cookie and will know that you had looked at that Justin Bieber album. In other words, activities online that are performed before or after leaving a site can be recorded and linked to you personally later on. Self Destructing Cookies is one of the best tools to combat this, as it destroys cookies shortly after you close the tab. Self Destructing Cookies is also useful in many other respects, and if you're interested in getting into the nitty-gritty, check out this page
While the add-on is fairly straight-forward, there are a few tweaks you can make depending on your preferences. First, you can change the "Grace Period" (the time between when you close a tab to when the cookies are deleted). The default for this setting is 10 seconds, which is useful for when you accidentally close a tab. If you want immediate deletion and a high level of security set it to zero. Another option you may want to change is the "Notifications" option. By default the notifications are on, meaning that every time the add-on deletes a set of cookies it puts a notification on the screen letting you know what it did. This can be interesting at first as you begin to understand just how effective it is, but it can also get rather annoying. I would try it out for a short while, but also would probably recommend turning notifications off at some point if you find you're going crazy.
The "Whitelist" option lets you tell the add-on which sites you trust. If you trust that the cookies from Reddit.com aren't going to be used to track you, you can tell Self Destructing Cookies not to delete any Reddit cookies when you close tabs. This means that you don't have to log in again when you return to the site. The last notable item in the options menu is "Statistics". Of course this isn't an option, but instead it allows you to see how useful the add-on is. My statistics read as follows: " Removed 204 cookies since 10/10/2013, 09:19:03 AM [a 3 hour period]. Of these, at least 14 were probably attempts to track you across the web".
The add-on is quite simple, but has a huge effect on your privacy. You can download it from the Mozilla Add-on website