The Electronic Freedom Foundation has released a white paper that reveals most Web browsers leave enough information about their configurations on Web servers that they are identifiable.
The EFF put up a web site, took data from 470,161 informed participants and found that among browsers with Flash or Java activated, 94.2 percent were identifiable (“unique” in their words.)
“By observing returning visitors, we estimate how rapidly browser fingerprints might change over time. In our sample, fingerprints changed quite rapidly, but even a simple heuristic was usually able to guess when a fingerprint was an “upgraded” version of a previously observed browser’s fingerprint, with 99.1% of guesses correct and a false positive rate of only 0.86%.”
And, if that isn’t scary enough, they said that those using anti-fingerprinting privacy technology will still be identifiable until a lot of people start using the same countermeasures.
White paper here: “How Unique Is Your Web Browser?”