Back in December I wrote an article here on the “Technical aspects of the censoring of Wikipedia” in the wake of the Internet Watch Foundation’s decision to add two Wikipedia pages to their list of URLs where child sexual abuse images are to be found. This list is used by most UK ISPs (and blocking systems in other countries) in the filtering systems they deploy that attempt to prevent access to this material.
A further interesting censoring issue was in the news last month, and this article (a little belatedly) explains the technical issues that arose from that.
For some time, the IWF have been adding URLs from The Internet Archive (widely known as “the wayback machine“) to their list. I don’t have access to the list and so I am unable to say how many URLs have been involved, but for several months this blocking also caused some technical problems.