If I'm reading it correctly, a recent Microsoft study of Bing and Hotmail traffic showed 80% of users could be uniquely identified using passive, server-side fi

If I'm reading it correctly, a recent Microsoft study of Bing and Hotmail traffic showed 80% of users could be uniquely identified using passive, server-side fingerprinting of just client IP address and User-Agent header. http://research.microsoft.com/pubs/156901/ndss2012.pdf http://research.microsoft.com/pubs/156901/ndss2012.pdf "User-agent strings combined with IP addresses have an entropy of 20.29 bits—higher than that of browser plug-ins, screen resolution, timezone, and system fonts combined."