Several readers responded to my previous entry on China’s censoring of Google.

Jeremy Leader pointed out that Google offers a cached copy of any page on the Web. Google’s cache would allow easy access to any blocked page, so any effective blocker must block Google.

Seth Finkelstein points to his previous discussion of overblocking due to the “need” to censor caches, search engines, and the like. The court decision striking down CIPA (the law that required libraries to use blocking software) even mentions this:

As noted above, filtering companies often block loophole sites, such as caches, anonymizers, and translation sites. The practice of blocking loophole sites necessarily results in a significant amount of overblocking, because the vast majority of the pages that are cached, for example, do not contain content that would match a filtering company’s category definitions. Filters that do not block these loophole sites, however, may enable users to access any URL on the Web via the loophole site, thus resulting in substantial underblocking.

Given the proliferation of indices, search engines, archives, translators, summarizers, and other meta-level tools on the web, the censor’s job is getting harder and harder. The people creating such sites surely outnumber the censors many times over.

Another person explained to me how to defeat China’s blocking, using simple methods well within the capability of an average Web user. The trick has two parts. The first part is to configure your browser to use any ordinary Web proxy outside China. The second part is just as easy, but I’d rather not say what it is. This method allowed access to any blocked site from within China, as of a few months ago.