Information Entropy of Your Browser and hence your online model

Your Browser is one of your identity card when you are online.
Information Entropy is a quantity depicting the information contained in the given data. Higher the multiplicity, higher the Entropy, better you are hidden in the population. The case is reverse if you want to stand out in the mass.
See some basics of Information Entropy in wikipedia here...

I found this nice article which enumerates the information theoretic basis applied to internet identity...
https://www.eff.org/deeplinks/2010/01/primer-information-theory-and-privacy

Using such theories, your uniqueness can be determined. Just like your fingerprint.
Click on the following link to see how trackable you are...
http://panopticlick.eff.org/index.php?action=log&js=yes

For my case, it says:

Currently, we estimate that your browser has a fingerprint that conveys at least 18.21 bits of identifying information.

Now, relate it to the personally identifiable  info that we put online.
This is quite striking and revealing on how the information we put online makes us more and more uniquely available to the web. I wonder what my online model would look like as stored in Google or Amazon.
Google Model: Given his online presence, what could be his next online purchase?
Amazon Model: Given his book browsing histories and buying habits, what could be his next online purchase?
  
No wonder how serving ads is going to be personally tuned in the near future (For instance, in the movie iROBOT, as Will Smith enters the supermarket, the billboard sign changes which was already personalized for him). That should not be too far :)

Side note:
I dont think that Facebook has deployed this strategy yet. It still displays yahoo/hotmail style fixed ads.  Given all the info available with Facebook, it could be huge!!! They should work on it instead of playing with privacy policy or similar controversial items.