You may have wondered how the ads that you see on the vast majority of websites these days (yes, this one included) have the extraordinary ability to "know" just what your interests are. There are a handful of companies that aggregate and collect information about you and your web browsing habits. They, in turn, use this information to figure out what interests you, then select ads they think you will react to, and serve those targeted ads to you. Creepy, huh?
How do they manage this? Well, any ad-bearing site you visit is under the control of at least one of these companies - this behavior is tolerated because ads bring revenue to the sites in question. When you visit a site, connections are made to these companies. They, in turn, read tiny little files on your hard drive called "cookies." (More on cookies in a minute.)
These files are controlled by them, and they can update the cookies with information about your habits. Of course, they also read these files to see where you've been, and what you did at the sites you actually wanted to visit. So: not only do they know what you do at the site you are currently at, they also can see what you've been doing elsewhere in the past. This type of cookie is known as a third-party cookie, because they are 'behind' the sites you consciously visit. How can you avoid this behavior? Fortunately, there is a way, but you have to consciously opt out of the process. (It would be much better if one had to opt in, but the ad industry, of course, has no appetite for that. Short of congressional intervention, I doubt it will ever happen.) Some tips:
First, make sure you visit this page. This site feels the same way as I do, and makes a conscious effort to warn its visitors - even to the point of showing a conspicuous pop-up about this the first time you visit it. They tell you where to go to opt out, as well as some good, free software that will clean the mess you no doubt have already accumulated on your hard drive. Also, check Ed Bott's good article about this. And another good one here. And here! As you can see, there's a lot of help out there!Another good source is Google. At this page, they will allow you to install a plug-in to Internet Explorer and/or Firefox that will trap third-party cookies and refuse to play the game. Additionally, they provide instructions for achieving the same effect in Chrome (my browser of choice) and Safari. No doubt other browsers can do the same - essentially, what you have to do is select an option that refers to suppression of third-party cookies. So, take a look in your browser's options and see what you can do.
If you use a firewall or anti-virus program (if you don't, you're asking for trouble), there may be ways they can also help. Face it, folks - we need all the tools available to us to fight this scourge.
Note on cookies: Not all cookies are bad. Most of the sites you visit these days will drop a cookie onto your hard drive so that they can make your browsing experience more pleasant. For example, some will "remember" where you left off the last time you visited, and resume at that point. Or, they will be able to recognize you automatically when you go there. Amazon, for example, will say "Hello, Fred" (or whomever) at the top of the page as soon as you get there. The cookie provides a key to their (hopefully secure) database which, in turn, provides info that instigates services like their 1-click ordering (which, btw, is patented - see tomorrow's post). Some websites become unstable or even unusable if you do not accept their cookies. Consequently, while you can refuse all cookies in all browsers, I do not recommend this action. Just don't let the nasty ones live on your hard drive!One more thing: Supposedly, the companies responsible for third-party cookies do not keep personal, identifiable information about you. But, let's face it, it's their word against ours. Spyware is a constant concern and, in my opinion, a valid one. Who do you trust? While I'm not a conspiracy theorist, I do value my identity and my privacy. I hope you do too. [So much for my promise of brevity!]
Update: I ran Spybot, one of the recommended (and free!) tools to search and destroy these evil third-party cookies. Here's the result. I'm publishing this because I think it highlights the necessity of keeping your system clean. This list shows all the perps, and the quantity of tracking cookies that were discovered. Adviva (2), BlueStreak (1), BurstMedia (6), CasaleMedia (9), Clickbank (1), CoreMetrics (1), DoubleClick (12), FastClick (7), LinkSynergy (3), MediaPlex (2), Omniture (9), Statcounter (8), Tradedoubler (3), WebTrends live (1), Win32.PornPopUp (11), Zedo (9). Grand Total? 85!
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