Comment by rvnx
6 years ago
They key in the wording is: "If usage statistics and crash reports are disabled, this number is chosen between 0 and 7999 (13 bits of entropy)."
"If, statistics are disabled."
In chrome://version you can see the active variations. It seems to be pretty big numbers to be significant, and so far haven't observed duplicates.
Since this header is generated server-side, you have only to believe I guess ? Plus why Doubleclick would need it :)
That's basically saying "even if you opt out, we'll still try to track you, just not as much." Very unpleasant, but then again I'm not surprised to see this attitude from Google.
Combine a few pieces of information like this and you get a decisively unique fingerprint.
For example identifying individuals at work behind the same ip address.