Sadly incomplete due to unspecified “changes in the development team” — perhaps the Orwell fans at Face-mazo-gle felt threatened and sent a hit squad — some Hungarians have released a neat Firefox plugin called Firegloves that fakes the otherwise uniquely identifying data your browser makes available to every site you visit.
Basically, your browser is more or less unique — compared with every other Internet user out there. The combination of browser version, screen resolution, whether or not you have Flash, etc., all make up a fingerprint. This is a terrible privacy hole.
No, this isn’t new. JonDoFox and Torbutton both provide limited workarounds for this. However, Firegloves is the first to take a really thorough crack at the problem. By systematically collecting “browser fingerprints” from Internet user-volunteers, they’ve identified the most common among each possible attributes and used those to create the most generic possible picture of your computer. From there, they tackle things like font detection (only allowing the most generic possible fonts to be queried, reporting the rest as “installed” no matter what) and plugins (you can still use VLC, scripts can’t tell you have it).
Why care about all of this? Go watch “Brazil”. The government over there’s gone public with some systems for spotting “pre-crime” (http://www.darkreading.com/security-monitoring/167901086/security/news/240144496/u-s-creates-system-to-look-for-future-crimes.html ) This means that the real systems are likely so well entrenched by now it probably is just a matter of one small bug before you get marked for who-knows-what instead of the real target. (or maybe you are the real target, but don’t realize yourself that you’re a ‘potential terrorist’)
(In all fairness the EU has started murmuring along similar pre-crime lines.)