FINDING SOURCES
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is illustrated by a study reported in 2009 by Arvind Narayanan and Dr.
Vitaly Shmatikov, from the University of Texas at Austin,
8
who developed
an algorithm by which they identied the names and addresses of anony-
mous Twitter, Flickr, and Live Journal users by looking at relationships
between all the members of a social network—not just the immediate
friends connected with members. They found that one-third of those
who are on both Flickr and Twitter can be identied from the completely
anonymous Twitter graph, despite the fact that the overlap of members
between the two services is thought to be about 15%. The researchers sug-
gest that the more social network sites are used, the more difcult it wil