Track This

Since I have an account with face­book, LinkedIn, flickr, xing and who knows where else, I’m prob­a­bly not expect­ed to be too con­cerned about per­son­al data pri­va­cy. But sur­pris­ing­ly I am. How­ev­er, some of the ben­e­fits of par­tic­i­pat­ing on these sites (poten­tial­ly) out­weigh the draw­backs of giv­ing out per­son­al infor­ma­tion. Also, on most sites, I have con­trol over how much I want to reveal about myself – which usu­al­ly is rather lit­tle.

What I didn’t real­ly care about until recent­ly is how web­sites can track my surf­ing habits. Each time a ban­ner ad is shown on a web­site, the ad serv­er that serves it can set a brows­er cook­ie or read it if it’s already been set. Con­tained in that cook­ie is usu­al­ly some num­ber that unique iden­ti­fies a user. They also know what site the ad was shown on. So if they served their ads on enough sites and if they want­ed to, they can tell from their data­base what cor­ners of the Inter­net I hang out in. Sure, there are ad-block­ers out there that will pre­vent this, but what about all the “social” sites? Every time I see a face­book like but­ton on a web­site and that but­ton is served from their serv­er, face­book will know I was there, be I a face­book user or be I not. You can’t ad-block this.

I start­ed car­ing about being tracked when I read about and tried the Col­lu­sion Fire­fox add-in. While you surf, this add-in visu­al­izes which site is (poten­tial­ly) track­ing you on which oth­er sites with their cook­ies. Just after a short while, there were so many dots and inter­con­nec­tions, I was flab­ber­gast­ed. And I’m not so often flab­ber­gast­ed.

There are a few things you can do to reduce the dam­age. First of all, turn on an ad-block­er like AdBlock Plus for Fire­fox. This is the Col­lu­sion out­put from vis­it­ing the front pages of spiegel​.de and heise​.de with ads turned on:

Col­lu­sion out­put with ads allowed

And this is what it looks like with­out ads:

Col­lu­sion out­put with ads blocked

Also, you can turn off third-par­ty cook­ies (i.e. cook­ies from web­sites oth­er than the one you are cur­rent­ly vis­it­ing)1. This will result in

Col­lu­sion out­put with ads and third-par­ty cook­ies blocked

Per­son­al­ly, I don’t believe in turn­ing off cook­ies com­plete­ly, since they can be quite use­ful. But in spite of turned off third-par­ty cook­ies, the Col­lu­sion out­put after surf­ing a while is quite con­vo­lut­ed – maybe read oper­a­tions on already present cook­ies are also shown; the doc­u­men­ta­tion is a bit light.

Tread light­ly out there.


1 Instruc­tions on how to turn off third-par­ty cook­ies for Fire­fox can be found here [Mozil­la].


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