 Can websites personally identify visitors?
Online anonymity is pretty much gone.  You can uniquely identify most visitors without cookies using a bunch of other exposed attributes.This site shows you how unique your system appears:
http://panopticlick.eff.org/When you combine things like screen-resolution, installed fonts, etc. you get a pretty-unique profile of each person.Bruce Schneier addresses the topic here:
http://www.schneier.com/blog/archives/2010/01/tracking_your_...How UberVu mapped this back to an actual email address is a separate matter - but I'm guessing they used the profile of his machine and connected it to a matching profile they had access to from some site he does authenticate with.Now extend that concept to Google.  They've got their digital hooks on millions of sites using Google Analytics.  They can map those hits back to an IP address that correlates to a GMail login and get a pretty good idea about where else their users browse.