initial testing on his Web site. In February and March 2002 he
repeated his testing of the 6,777 URLs originally found to be
blocked by at least one of the blocking products, in order to
determine whether and to what extent the blocking product vendors
had corrected the mistakes that he publicized. Of those URLs
blocked by N2H2 in the October 2001 testing, 55.10% remained
blocked when tested by Edelman in March 2002. Of those URLs
blocked by Websense in the October 2001 testing, 76.28% remained
blocked when tested by Edelman in February 2002. Of those URLs
blocked by SurfControl's Cyber Patrol product, only 7.16%
remained blocked, i.e., Cyber Patrol had unblocked almost 93% of
the Web pages originally blocked. Because the results posted to
his Web site were accessed by an employee of SurfControl (as
evidenced by Edelman's records of who was accessing his Web
site), we infer that Cyber Patrol had determined that 93% of all
6,777 pages, or 6,302 Web pages, were originally wrongly blocked
by the product.
Two other expert witnesses reviewed subsets of the list
of Web pages that Edelman compiled. Dr. Michael T. Ryan,
Director of the Rare Book and Manuscript Library and of the
Center for Electronic Text and Image at the University of
Pennsylvania, reviewed a list of 204 sites that Edelman forwarded
to him in order to determine their appropriateness and usefulness
in the library setting. Because the sites that Ryan reviewed
were not selected randomly (i.e., they were chosen by plaintiffs'
counsel), his study says little about the character of the set of
6,777 sites that Edelman compiled, or the total amount of
overblocking by the four filtering programs that Edelman used.
Anne Lipow, a practicing librarian for more than 30 years
and the director of a library consulting firm, also reviewed the