combination of these two deficiencies. Coupled with the extent to which savvy Internet users
can evade the filtering regime, state authorities undertaking technical filtering know that they
cannot succeed completely.
The public policy questions to which these problems give rise are many and complex. If a
filtering regime cannot be implemented in an accurate manner, should it be undertaken at all?
Under U.S. law, these shortcomings make any such system constitutionally suspect, if not
outright infirm, but other legal systems would likely draw a different conclusion. Is overbreadth
or underbreadth preferable in a filtering regime? States often respond by turning more and
more to intermediaries—search engine providers, ISPs, cybercafe ´ owners, and so forth—to
make these decisions on the fly.
Filtering and Overbreadth Internet filtering is almost impossible to accomplish with any
degree of precision. A country that is deciding to filter the Internet must make an ‘‘overbroad’’
or ‘‘underbroad’’ decision at the outset. The filtering regime will either block access to too
much or too little Internet content. Very often, this decision is tied to whether the state opts to
use a home-grown system or whether to adopt a commercial software product, such as
SmartFilter or Websense, two products made in the United States and licensed to some
states that filter the Internet. Bahrain, for instance, has opted for an underbroad solution for
pornography; its ISPs appear to block access to a small and essentially fixed number of
blacklisted sites. Bahrain may seek to indicate disapproval of access to pornographic material
online, while actually blocking only token access to such material, much as Singapore does.
United Arab Emirates, by contrast, seems to have made the opposite decision by attempting
to block much more extensively in similar categories, thereby sweeping into its filtering basket
a number of sites that appear to have innocuous content by any metric.
Most of the time, states make blocking determinations to cover a range of Web content,
commonly grouped around a second-level domain name or the IP address of a Web service
(such as www.un.org or 66.102.15.100), rather than based on the precise URL of a given Web
page (such as www.un.org/womenwatch/), or a subset of content found on that page (such
as a particular image or string of text). This approach means that the filtering process will
often not distinguish between permissible and impermissible content so long as any impermissible content is deemed ‘‘nearby’’ from a network standpoint. In the case of the above example, the WomenWatch site was unavailable in Vietnam not because of the state attempts to
block all sites relating to gender equality issues ( judged by the availability of all other similar
sites we tested), but because of a block placed on the entire www.un.org domain.
Because of this wholesale acceptance or rejection of a particular site—which may or may
not correspond to a given speaker or related group of speakers—it becomes difficult to know
exactly what speech was deemed unacceptable for citizens to access. Bahrain, a state in
which we have found a handful of blocked sites, has blocked access to a discussion board
at www.bahrainonline.org. The message board likely contains a combination of messages
46
Jonathan Zittrain and John Palfrey
can evade the filtering regime, state authorities undertaking technical filtering know that they
cannot succeed completely.
The public policy questions to which these problems give rise are many and complex. If a
filtering regime cannot be implemented in an accurate manner, should it be undertaken at all?
Under U.S. law, these shortcomings make any such system constitutionally suspect, if not
outright infirm, but other legal systems would likely draw a different conclusion. Is overbreadth
or underbreadth preferable in a filtering regime? States often respond by turning more and
more to intermediaries—search engine providers, ISPs, cybercafe ´ owners, and so forth—to
make these decisions on the fly.
Filtering and Overbreadth Internet filtering is almost impossible to accomplish with any
degree of precision. A country that is deciding to filter the Internet must make an ‘‘overbroad’’
or ‘‘underbroad’’ decision at the outset. The filtering regime will either block access to too
much or too little Internet content. Very often, this decision is tied to whether the state opts to
use a home-grown system or whether to adopt a commercial software product, such as
SmartFilter or Websense, two products made in the United States and licensed to some
states that filter the Internet. Bahrain, for instance, has opted for an underbroad solution for
pornography; its ISPs appear to block access to a small and essentially fixed number of
blacklisted sites. Bahrain may seek to indicate disapproval of access to pornographic material
online, while actually blocking only token access to such material, much as Singapore does.
United Arab Emirates, by contrast, seems to have made the opposite decision by attempting
to block much more extensively in similar categories, thereby sweeping into its filtering basket
a number of sites that appear to have innocuous content by any metric.
Most of the time, states make blocking determinations to cover a range of Web content,
commonly grouped around a second-level domain name or the IP address of a Web service
(such as www.un.org or 66.102.15.100), rather than based on the precise URL of a given Web
page (such as www.un.org/womenwatch/), or a subset of content found on that page (such
as a particular image or string of text). This approach means that the filtering process will
often not distinguish between permissible and impermissible content so long as any impermissible content is deemed ‘‘nearby’’ from a network standpoint. In the case of the above example, the WomenWatch site was unavailable in Vietnam not because of the state attempts to
block all sites relating to gender equality issues ( judged by the availability of all other similar
sites we tested), but because of a block placed on the entire www.un.org domain.
Because of this wholesale acceptance or rejection of a particular site—which may or may
not correspond to a given speaker or related group of speakers—it becomes difficult to know
exactly what speech was deemed unacceptable for citizens to access. Bahrain, a state in
which we have found a handful of blocked sites, has blocked access to a discussion board
at www.bahrainonline.org. The message board likely contains a combination of messages
46
Jonathan Zittrain and John Palfrey