Reaction to Digital Shadow article

I was so shocked on how companies can track you down and see everything you do. Last year Mrs Long told us how companies track you down so that they can post advertisements that you are interested in on your facebook. I never knew that they could see everything you do on every site. Its kind of scary, now when i surf on the web part of my brain is always thinking who could be watching me right now, this is why im considering downloading the program to see who is tracking you down at the moment. However i never ever look at the advertisements when i'm in Israel because they are all in Hebrew and i cannot read them. But when I'm in Spain i always click on them because they always show water sports which interest me the most.