Thanks for all the insightful comments about how this "didn't work for you" or "I'm paranoid so I survived this"?
It works. It works enough of the time and on enough browsers to be very relevant to anyone who cares about the privacy/security of internet users at large.
This is an impressive proof of concept, and an important thing to be discussing, yeah?
[EDIT] To clarify, I tested this on Firefox 8.0.1 on my 2011 iMac with Lion and it worked flawlessly one by one as I visited the sites "Facebook, Reddit, Flickr", they turned from gray to green in each subsequent test.