BenEdelman writes "Recent Internet filtering efforts reach from China to Pennsylvania. While these systems differ in their substantive target (political speech versus child porn), they share a lack of granularity: Both operate, by and large, at the level of a web server's IP address. As a result, when a single server hosts many web sites, these filtering systems tend to overblock, for the crudeness of the filtering system lets filter operators block targeted content only by blocking extensive other content that happens to share the same server.
In recent work, I have analyzed the rate at which web sites share web servers -- determining that more than 87% of web sites share their web server with at least one other site, and more than two thirds of sites share with fifty or more sites. The net result is blocking even beyond censors' apparent intentions, and typically overblocking of sites that censors and stated filtering policies would deem innocuous. My new Web Sites Sharing IP Addresses: Prevalence and Significance provides further details and analysis.
Prior Lawmeme coverage:
Empirical Analysis of Internet Filtering in China (Dec 3, 2002)
Help Test the Great Firewall of China (August 29, 2002)
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