I just tested at Panopticlick, and it told me my browser is completely unique. Just like it said the last 8 or so times I've been to Panopticlick.
So I question how meaningful that is. Yes, it's pulling enough info to uniquely identify a browser for now, but in a week I'll add a plugin, remove a plugin, change a setting, update Firefox, whatever and the tracking will be lost.
Edit: Also, browsers could be patched to randomize some of the information Panopticlick is using, like the exact way the HTTP Accept header is written, and the order in which plugins are reported.
So I question how meaningful that is. Yes, it's pulling enough info to uniquely identify a browser for now, but in a week I'll add a plugin, remove a plugin, change a setting, update Firefox, whatever and the tracking will be lost.
Edit: Also, browsers could be patched to randomize some of the information Panopticlick is using, like the exact way the HTTP Accept header is written, and the order in which plugins are reported.